Tinker

Boush the Tinker is a ranged intelligence Hero who relies heavily on his assortment of nukes for ganking and pushing. He is able to reset the cooldown on his abilities, and in conjunction with Boots of Travel gives Tinker global mobility rivaled only by Nature's Prophet, making him a constant threat. His abilities' mana costs are very high, so his ultimate, Rearm, and Boots of Travel serve a long way towards going back to the base fountain to restore his mana. Tinker needs to farm his Boots of Travel as soon as possible for his ganking and pushing potential to really rise. If he farms it too late, he might not be able to cope up with it. Therefore it is recommended for Tinker to solo mid.

Early Game
Tinker should almost always solo mid (soloing bot as Radiant and top as Dire with a tri lane also works). There are many reasons behind this. Tinker has two very damaging, strong scaling and reliable nukes (Laser and Heat-Seeking Missile making him one of the strongest burst damage heroes in early levels) giving Tinker's insane ganks early game. Tinker is also very mana intensive hence a solo mid lane with bottle will give him the mana that he needs from runes. Furthermore Tinker's abilities have very high mana costs, and although Tinker has fantastic a starting Intelligence of 27, his Intelligence gain of 2.2 leaves a lot to be desired for a nuker combined with his high mana costs, making it more imperative for Tinker to use Bottle with Runes.

Tinker also requires an early Boots of Travel to stay relevant past early game and due to his incredibly strong mid solo this gives him the room to farm this much needed item.

Another reason Tinker should solo mid is even though he does very high damage early game, he has no escape abilities and no utility barring his miss on Laser. This leaves him very vulnerable to ganks himself (side lanes are much easier to gank than mid lane) and also very vulnerable to dying in the lane, since he has no ability to defend himself when he gets focused by 2 heroes. His 2 main nukes also have a very high CD, which makes him even more vulnerable in side lane after Tinker does his burst.

Mid Game
Tinker's mid game is one of his worst stages in the game and also in general when compared to other heroes. Although Tinker still has his two very high damage nukes, this is all he has to offer in skirmishes and team battles. March of the Machines is a much more useful as a farming tool than a ganking/team fight tool due to how difficult it is to position properly and Tinker's weakness of having no escape ability, coupled with his fragility and minimal utility and raising health costs on opposing heroes making his burst less painful are the reasons behind his weak mid game in general.

Tinker should mainly be using this time for farming/pushing and counter ganking. If all went well with early game he should have a Boots of Travel at this point of the game allowing him to teleport to a lane, drop a couple/few March of the Machines's and teleport back to base to Rearm. This is even more important due to the fact that Tinker requires items to stay strong in late game due to how Rearm works with item abilities and so he should definitely spend this period of the game farming and not running around and ganking (leave this job to other heroes who do this a lot better). Do not completely abandon your team however, remember that Tinker is very good at counter ganking, mainly due to how easy it is for him to Teleport to a tower/creep at all times and he is also an excellent pusher so use this to your advantage.

Late Game
Tinker's weak mid game is made up for by his very strong late game. Suddenly a hero with no utility apart from his miss can end up having one of the highest utility heroes in general. Tinker can do everything, he is an insane pusher with Shiva's Guard, Boots of Travel and Manta Style, deals good damage (even higher if Tinker chose to get a Dagon), amazing survivability a Shiva's Guard, Black King Bar, Linken's Sphere and Manta Style as well as an incredibly strong disabler with Scythe of Vyse and Orchid Malevolence. Furthermore, Tinker actually has the ability to farm these items very easily due to March of the Machines,Shiva's Guard,Manta Style and Rearm.

There is very little an opposing team can do to deal with a geared up late game Tinker. Although he may not have as much raw damage/survivability as other carries he makes up for it in every other area. Silences (apart from Doom) that once gave Tinker massive problems can be countered with Manta Style and Black King Bar, single target spells are dealt easily with a Linken's Sphere and Black King Bar. A Manta Style, Black King Bar and Shiva's Guard make him very difficult to kill/chase/finish off and ontop of all of this he can push multiple lanes at once exceeding Nature's Prophet main strengths. He also does very good AoE damage with Shiva's Guard combined with March of the Machines (and unlike in mid game Tinker at this point has enough survivability to properly position himself to land March of the Machines in team battles)

Tinker, like Storm Spirit,Outworld Destroyer and Necrolyte, is one of the few heroes that scale very well with Mana/Mana Regeneration further improving his late game strength. There is no limit to how much mana Tinker can use, but he becomes infinitely stronger the more mana/mana regeneration he has! Furthermore he can select which of the previously mentioned items he wants to buy to counter the enemy teams composition without gimping his own item build, because he is equally strong with all of the items mentioned.

Blink Dagger/Force Staff also gives Tinker great mobility and initiation.

A well timed Doom along with focus fire, or a team full of ultimate's that are AoE and go through Black King Bar are one of the few strategies that can deal with a properly geared late game tinker. Also note that even though a late game Tinker is very strong, he requires quite a bit of skill and micromanagement to play because of the sheer number of active abilities that Tinker has to deal with coupled with Rearm. Also Tinker naturally low mana pool (for a nuker) becomes greatly mitigated due to the plethora of items available for him to cover this weakness, and his ability to go back to base to regenerate his mana and return in minimal time.

Note that even though Black King Bar is not refreshed with Rearm its still a very good item to get for Tinker mainly because of how difficult it becomes to kill him when combined with other items such as Shiva's Guard and Manta Style as well as Linken's Sphere.

Tips

 * Laser is an extremely powerful nuke that ignores magic resistance. Use it as primary source of damage for the Tinker.
 * If there is only one opponent on your lane, you should max out laser first, as it deals high damage per mana cost compared to heat seeking missle. The blind effect should never be underestimated as it acts as a pseudo-disable on hero physical attacks.
 * Heat Seeking Missile has a really long range. With rearm, you can spam a barrage of heat seeking missiles as to harass enemy heroes.
 * March of the Machines is a perfect farming tool. It's a bit tricky to aim though. You can overlap several March of the Machines using Rearm to deal massive area of effect damage.
 * The Tinker is arguably the best solo mid hero. He can constantly harass his lane opponent with Laser and Heat Seeking Missile forcing him to stay away from creeps. And if he gets pressured by roaming heroes he can always farm safely using his March of the Machines from afar.
 * If you do solo mid as the Tinker, a bottle is a wholly worthwhile item. Not only will bottling runes benefit you in your ganks, but once you do get your Boots of Travel, you will be back at the Fountain more often than most, making bottle refilling easy even if you can't find a rune.
 * You can stack commands by holding shift to prevent unintentional Rearm interruptions. The Tinker will perform stacked commands right after finishing Rearm.
 * Boots of Travel is a commonly built item on Tinker. Used in conjunction with Rearm, it allows you to teleport around the map quickly.
 * Once the Tinker gets Boots of Travel and Soul Ring, start teleporting back and forth between lanes and fountain to farm everything on the map.
 * Participate in ganks whenever you get a chance. "Missile, Laser, Rearm, Missile combo" should be enough to finish off any fleeing enemy early-mid game.
 * Always kill enemy silencers and disablers first because they can ruin your spell combos.
 * The Tinker can permanently disable and kill enemy carries in the late game. Simply repeat "Scythe of Vyse, Missile, Laser, Rearm" cycle till your target is dead. Make sure you have sufficient mana pool and you're performing everything quick enough.
 * A Force Staff is another useful item for the Tinker. It's cheap, provides Intelligence, and has an active ability that, in conjunction with Rearm, can get you out of sticky situations in a heartbeat. A Blink Dagger can be used for a similar purpose, but because it does not provide additional stats, it is usually preferable to buy the Staff instead.
 * Another popular item to get as the Tinker is the Dagon as it works well with Rearm to deal massive burst damage provided a sufficient mana pool is present. The combo of Dagon > Rearm > Dagon is deadly when paired with Heat Seeking Missile and Laser.
 * Be careful when you use your spell combos as the Tinker is extremely mana-hungry. A few lasers and you will quickly find yourself without mana if you're saving up for Boots of Travel or Scythe of Vyse.
 * When facing auto attack-heavy heroes such as Lone Druid and Ursa, it may be wise to build Heaven's Halberd. In conjunction with laser, you effectively can disable auto attackers up to 6 seconds for melee heroes and 7 seconds for ranged heroes. Adding Scythe of Vyse up on this brings a disable of 9.5-10.5 seconds. Using Rearm properly allows you to completely shut down certain heroes.
 * Orchid Malevolence in conjunction with Rearm allows you to permanently silence casters. Use this on caster heavy teams.
 * Basically when tinker acquired Boots of Travel and enough mana to rearm and withdraw, he can confuse any opponents since tinker's route always makes the opponent get forced to defend tower primarily and tinker's route mostly like Lane-Fountain-Lane, again and again.

Trivia

 * The Tinker's voice actor, Harry 'Hal' Robins, also voiced Dr. Isaac Kleiner in Half-Life 2. Many of Tinker's voice lines reference characters and events from the Half-Life universe. In addition, the name "Violet Plateau" is quite similar to "Black Mesa," and the events described in Tinker's backstory are remarkably similar to the events of Half-Life.
 * The Tinker's alternate/fun name in DotA was "X!!", name of a professional DotA player.
 * Tinker's line 'I think! Therefore I am!' is a philosophical statement proposed by René Descartes. It's original Latin words are "Cogito ergo sum."