Hearthpwn

You need to exploit Mech Synergy and Innervate to fill up the board as quickly as possible and start buffing them with Spare Parts or Power of The Wilds waiting to grind the opponent down. You should also play for board control when you have valuable trades, also because you should always have board control in the early game. Play around big removals if possible and get ready to burst the opponent turn 5-6! 

Innervate

Not much to say about one of the strongest staple cards of this class

Living Roots

One of the best card to come out of TGT set. Played as board presence, removal, or finisher, this card has many different uses. Irreplaceable

Clockwork Gnome

Amazing card for Mech synergy, and the Spare part that we receive upon his death can be used in a million ways

Power of the Wild

This card is often used in Token Druid decks (of which this deck is partially inspired to) and can be used to buff our little minions into scary war machines or as a 3/2 for 2 in the worst case scenario

Annoy-o-Tron

The most annoying Mech in existance. Little to say that we don't know already: Mech synergy, amazing resistance to removal and can protect our minions

Darnassus Aspirant

Another amazing card for the druid to come out of TGT. This is the other way that we have to ramp out of control while keeping board presence. 

Mechwarper

The core of every Mech deck. Its ability combined with an Innervate can give us the possibility to completely unload our hand in 1 turn, to just take the game by storm with our army of Mechs

Savage Roar

First part of the most broken combo in all Hearthstone. Totally viable without his companion Force of Nature because we can use our board full of Mechs to launch a deadly assault to the enemy life total. The sole reason why you can close the game by turn 4/5 with the right hand

Harvest Golem

Another core Mech for decks of this tribe. I use it in single copy because in some match ups is preferable to Spider Tank, and vice versa. Warrior, Rogue, Mage, and Paladin for example are good match ups to keep Harvest Golem in our hands

Spider Tank

Read the description above. Ditto. Spider Tank is more favorable vs Druid, Hunter, Warlock, Priest and Shaman.

Tinkertown Technician

Little gnomes with strong Mech synergy. When played with a Mech in Play the become a 4/4 and they give us a Spare Part to mess around with. A 4 mana stat/effect for 3 mana? Yes please!

Swipe

Staple removal in all druid decks. Used to wipe the board or to push for lethal, especially behind Taunts. A must keep vs Paladin and Warlocks for Muster for Battle and Imp-losion

Keeper of the Grove

One of the strongest Druid minion in terms of value and versatility. The silence effects can be used on enemy Taunts or buffs, or we can use it to remove Freeze effects from our minions. The best way to use it is to silence our own Fel Reaver to make them blank 8/8 for 5. Value!

Piloted Shredder

Creating a Mech deck without using Piloted Shredder is a sin. Especially when the 2 drop that comes out from the deathrattle effect is another Mech! 

Fel Reaver

The shining star of the deck. Who needs legendaries when you have a 8/8 that crunches the opponent face? Using Innervate to play this minion by Turn 2-3 (sometimes even 1) is a straight up game winner 90% of the times. In other cases tho is a card to use carefully: we should play this only when we are ready to close the game in the next 2-3 turns, or our deck will crumble in dust in a matter of seconds! Not that is a problem when you win the game but just don't throw it randomly on the board.

Force of Nature

Second part of the strongest combo of them all. Don't be scared of using it as a 6 damage for 6 mana card to mantain board control. Sometimes played on turn 9 in conjunction with Savage Roar lets us deal 14 damage with an empty board. Now think about doing it in Turn 7 with Innervate with a board already full of Mechs. Someone said the word OVERKILL?.... Yes, me. Many many times.

In my experience with this deck I found Dr. Boom too slow. Fel Reaver and Force of Nature are already 4 cards that can screw up our massive openings by clogging our hands. The only way that I could foresee using Dr.7 in our deck is to change this 4 "late game" cards. Another candidate could be Nourish, because we practically always go topdeck mode by turn 3-4. Drawing Nourish could give us some extra steam to flood the board with. 

A combination that I would like to try is 1x of each of the aforementioned cards. Generally Dr. Boom subs one of the Fel Reaver, and Nourish can sub Force of Nature, or even both of them. 

If you don't feel confident with Darnassus Aspirant and you want more Mech synergy you can sub 2x Cogmaster in and you're good to go. 

Always try to get the best synergic hand exploiting 1 mana drops to get a perfect smooth curve. Don't be scared of keeping Innervate in your starting hand if you have a turn 1 Spider Tank or a best drop later. Cheating the mana curve is really valuable. By turn 3-4 you should have an empty hand (not counting Force of Nature and [cards]Fel Reaver[/card])

WARRIOR,  PALADIN, ROGUE, MAGE

Keep Harvest Golem if you have coin

WARLOCK, SHAMAN, HUNTER, PRIEST, DRUID

Keep Spider Tank if you have coin

This is the report of all the games done from rank 7 to Legend and yes, I have a 100% winrate vs Shaman (pretty much all face/mech/overload you name it). 

And this are the match ups from rank 4 3 stars in EU to Legend