I've been playing Gazlowe since he was released in Beta. He's always had a place in my heart as my favorite Goblin (Time is money friend). So this guide is a tribute to him. Basically I'm not sure if I'm the best Gazlowe player out there but I have some tips and tricks I've learned. So this is my guide for you:

Gazlowe is a sideline fighter, He likes it when people walk into his setup. So you have to be thinking about side lanes that you can team fight near or be right in the middle. Kind of like Sgt Hammer just think *safe distance away*.

I suggest using Scrap to recharge your abilities. Scrap recharges your abilities at three (3) times their rate and restores thirty (30) mana 1 * 3 * 3 = 9. This doesn't seem like much, and your right it is not. However, with the level 1 talent to make it 4 times the rate the equation goes from nine (9) to twelve (12). [1 * 4 * 3 = 12]. Twelve (12) seconds is the cooldown cost of Deth Lazor plus you get 30 mana back from each scrap picked up. This means that every three (3) seconds assuming there is a piece of scrap nearby, you can fire a Deth Lazor.

Scrap does not do a multiplicative stack it is only additive so the more you pick up at once the more you cooldown in the three (3) seconds you only gain twelve (12) seconds per scrap. If you Grav Bomb 3000 then pick up ten (10) scrap then you can Grav Bomb 3000 again in three (3) seconds. So word of advice. Since normally there aren't ten (10) scrap laying around for you to pickup, you need to pick up your scrap one at a time count to three (3) seconds before picking up another one. Do not pick up scrap just before firing your Deth Lazer because your Deth Lazer goes on cooldown after you finish casting it. If you just used your Grav Bomb 3000 and you'd like it back up, Just go back to base and put down turrets one at a time and blow them up after the cooldown has reset on them to pick up scrap. Doing this about eight (8) times normally makes it so your ready to Grav Bomb 3000 again.

You run out of mana pretty quickly in this build. That is because you are outputting a lot of damage in very little time. It is okay to run out of mana. Just make sure that if you are close you are backing up ready to go back to base and run back out to the field. The Healing Fountain is a good stop if you have are about half way. (Assuming you still have one you can use)

All of the time::
It is pretty simple, Stand in the BUSH! Put your turrets in the BUSH! Don't be obvious about your position. Don't Deth Lazer in the middle of the lane Unless you are luring, or in a bind and need the slow. Always stand on the outside's of team fights (Just like Sgt Hammer), if you are level 20 you have a huge advantage with damage, Every turret does an aoe 300 damage, if you have five (5) turrets down, that is an extra 300* 5 = 1500 damage AOE every six (6) seconds.

Lane Pushing::
Always put your turrets in the line of fire of Towers. This wastes the towers ammo and gives the minions something to attack. It also forces you to generate scrap for yourself so you can keep the Deth Lazer going. That turret is doing work for you. The only time you should be using D to recycle a turret is if you want the 30 mana / the cooldown for Grav Bomb 30000 or the turret is in a location that it will just timeout and not do any additional damage. There is no other reason to D a turret. Let it do its thing while you are off somewhere else getting a merc camp or pushing a different lane. You give your team experience for things that turret hit.

HEALER, if you can Deth lazer the healer you should.
Your team's current focused character
As many as you can.

All Maps Build:
As Gazlowe or other side line hitters, To start go bottom or top. There is no need for you to suffer the harassment that mid gets, you don't have any useful escapes until level thirteen(13).

If you are pushing a lane and know where the other people are Do the basic rotation:
Drop a turret in between you and their minions.
Charge and fire Deth Lazer on their minions.
D the turret and pick up the scrap.
Mount. (This is freaking important) (Find a Bush, get ready to recall)
Watch the map, still no-one interested in you, run up to the next opposing teams minion wave. and repeat.

If they are ranged, DO NOT GO INTO THE MIDDLE OF THE FREAKING LANE. Hide in a bush. Bushes make ranged people melee people.

If they are melee, Perfect you got lucky. Put a turret down at the back of your minion line, put a turret down at the front of your minion line, and Deth Lazer the melee while focusing on their minions. If he comes at you just auto attack him, no worries with your minion wave and two turrets and your auto attack, hes going to die unless hes Cho'Gall, Thrall or Butcher. (In which case you should be keeping your distance).

Turrets:: (Placement Guide)
Place in Bush and wait with them for Suprise Deth Lazer (Unless they are aoe) then Don't wait with them lure them to the turrets and then as they are running away Deth Lazer them, if they are chasing you still then auto attack them.

Place in lane closest to the Opposing Teams Towers (take hits for your minions and your teams players) because they have the Highest Agro in the game. Teammate in trouble no problem place a turret down and the cannon tower will shot it instead.

Place about five (5) turrets away from your front gate if you need to back and have mana to spend on a couple of turrets. At that distance the opposing teams minions will not waste your Cannon Tower Attacks and be held off at that location until your next minion wave catches up.

Deth Lazer::
Bread and Butter skill here people. Clearing a minion wave you ran up to and don't have minions to take hits for you no problem. Drop a turrent and charge the Deth Lazer. D the turret pick up the scrap to recharge Deth Lazer and another turret for placement.

If you are fighting a Cho'Gall, just work off of surprise Bush Deth Lazer recycle turret, there really isn't anything you can do It's better to just Deth Lazer him from as far away as you can. (*Side Note*) You can get a lot of kills on Cho'Gall if you know how to body block him which is strongly recommended since you don't do much damage to him any other way.

If you are fighting a Thrall, He has his one heal see if you can kite him around your minions.

If you are fighting a Butcher, make sure you have an escape from the Charge -> Hamstring combo.

If they are Ranged but shoot line attacks (Li'Ming, Jaina) Then always keep some turrets in between you and her. Run through them if you have to, try to keep a safe distance away from your turret so you don't suffer form area damage.

If they are Ranged but are like Kael'thas were its just click and damage. Then keep your distance and rotate Deth Lazer. He'll have to back because Deth Lazer hurts every six (6) seconds.

If they are heroes like ( Illidan, or Artanis) that gain charges by auto attacking, Don't let them freaking auto attack you you, walk away, run around your turrets while they chase you discourage them by placing a bomb right where you are standing and don't move from there, level 13 Deth Lazer them to slow them down.

If you are fighting a Stiches, always keep a charge of Turret ready to intercept the Stiches pull. Just place the turret in-between his chain coming at you and you.

If you are fighting a Chen, don't wait around there, keep your turrets away from you but close enough to hit Chen. Charge your Deth Lazer. (Don't waste your time Auto Attacking, if you don't think you'll kill him then just back to your base, heal up / mana up and head back to lane.