As the name would suggest, Gaige the Mechromancer specializes in summoning a human-sized Deathtrap robot, who drifts around like a flying ghost and smacks bandits around with a strong melee attack.. Like the Commando's turret, he does have a health bar and can thus be destroyed, though he still acts as a great distraction that takes the heat off of you long enough to line up a carefully placed headshot. The Deathtrap lasts for a good while (about 30 seconds or so), but its 60 second cooldown is among the longest of the five classes. (Side-note: Gaige might as well be Tiny Tina's older sister.)
The Mechromancer's three skill trees offer extremely different strategies and you can experiment with them here. The Best Friends Forever tree primarily protects the Deathtrap from being destroyed while giving Gaige some added survival bonuses. The first two skills in the tree are actually among the strongest starting skills: Close Enough allows Gaige's bullets to ricochet (up to 50% of the time) and hit a nearby target, which is great for all gun types but especially for SMGs and other DPS-styled guns with a high fire rate; and Cooking for Trouble serves as solid health recovery in between battles while Gaige's gun is fully loaded.
Other highlights in the BFF tree help keep both Deathtrap and Gaige from falling too early. Buck Up instantly restores one ally's shield, likely Gaige's, which makes summoning Deathtrap a good trump card in case you get hit by a badass unexpectedly. Upshot Robot goes a step further by extending Deathtrap's duration by 5 seconds per kill, and 20% Cooler further down in the tree can reduce Deathtrap's cooldown to 42 seconds. The final ability, Sharing is Caring, gives Deathtrap a duplicate of Gaige's shield; here, I suggest equipping a Nova shield with a low recharge rate to give him a strong AoE counterattack.
The center tree, Little Big Trouble, is all about elementals (almost more than the Siren), particularly the Shock element. It's an interesting choice, mainly because anti-Shield guns aren't that effective unless you're facing robots; with this tree, though, the shock element becomes deadly. Shock Storm creates a continuous Electrocute damage (different from Shock damage, apparently) to nearby enemies every time Deathtrap kills an enemy and every time you kill an enemy with a critical hit. Needless to say, this is an incredible skill for snipers and is especially useful in narrow hallways and tightly enclosed spaces. Electrical Burn doubles down on this by giving you a chance to add burn damage on top of that; it's like gettting continuous damage grenades for free.
The LBT tree turns Deathtrap into a weapon elementalist with The Stare dishing out continuous Burn Damage and One Two Boom allowing Gaige to shoot an orb for a huge amount of Shock damage. The final skill, Make it Sparkle, converts Deathrap into whatever elemental type you wish. I also have to give a shout-out to Interspersed Outburst, which automatically gives Gaige a chance to slag an enemy as a first strike. It's yet another skill that pairs well with any gun type.
The last tree, Ordered Chaos, is the most complicated tree with high-risk, high-reward skills that give Gaige both bonuses and penalties at the same time. The whole tree is based around the Anarchy skill, which steadily boosts Gaige's gun damage at the cost of an accuracy penalty, as long as you never manually reload. If you prematurely reload, all the effects of Anarchy go back to zero. Here, I recommend using an assault rifle or SMG that either has burst fire while zoomed or one where firing increases accuracy (or both) to counter-balance the penalty.
The Discord skill alleviates some of the pressure from the Anarchy skill both by allowing Gaige to turn off Anarchy temporarily for a few moments of health regenerated and increased accuracy and fire rate. Since Discord is activated by prematurely reloading, instead of all of the Anarchy stacks going back to zero, they merely decrease at a fast pace. If the number of Anarachy stacks do drop to zero, though, the Rational Anarchist skill helps jump Gaige from 0 Anarchy stacks to 25 Anarchy stacks. Combined with the final skill, With Claws, almost permenantly turns your melee attack into a strong, health-regenerating, two-swing swipe that would make Zer0 jealous.
Lastly, if you're going for Ordered Chaos, it's worth looking into supplementing the Nth Degree skill, which has some bullets ricochet if you hit an enemy, with the Close Enough skill from the Best Friends Forever tree. With all the inaccuracy brought upon by the Anarchy skill, having a 50% ricochet chance of hitting even if you miss is a huge help.
Have any more tips with Gaige the Mechromancer? Share them below. They may even end up in this guide!