So here’s the thing, I have an OP8 Zer0 and everything I need for a Melee build but I have never played Melee Zer0.
Since I’m just going to jump into endgame Melee action, without much incite into that play style, I thought I’d ask the professionals. Is there anything I should know or is it pretty straight forward?
May I ask what your build was prior to stepping into melee? As in, have you ever used a roid shield or any of his melee skills (Killing Bl0w, C0unter Strike, even Execute)? If not, I would start by going down to an easier level just to practice with them to work on their mechanics without the frustration of lethal riposts. C0unter Strike, for example, took me some practice before I was able to mentally time it without looking directly at the icon. Execute with Many Must Fall is good to practice if for no other reason than getting the timing/cadence of that down, since the usual indicator of the progressive sound gets out of whack, and you can’t rely on that to tell you when you’re near the end of Decepti0n (and timing it around kunai bursts so you don’t eat them yourself is important). If you haven’t used a roid shield before, there’s some timing to learn when stripping your shield and getting that party started.
You can certainly just jump into OP8 and give it a spin, but let us know what melee skills you have practiced with, and we can go from there.
Try a bit of melee mobbing at op0 with a Love Thumper first to learn the process of when to slag, throw grenades, enter Deception, throw Kunai, switch to the Rapier, go for the Execute and switching out of the Rapier once visible again. I believe videos from op8 peak runs with the Hide of Terra are good examples of how to grasp the basics.
I’m only @OP1 with my melee Zer0, but maybe it helps a bit.
My Spec: http://bl2skills.com/assassin.html#505001000055055105015105515151
Equipment you should get is mostly listed in the Top Gear Thread, I’ll go into the most important stuff any ways.
Grog Nozzle - Ruby won’t quite cut it any more on OP levels to Healthgate properly. Bladed if possible.
Rapier - Slag if possible, but it doesn’t matter much, you won’t fire the Gun often.
2 Slots Situational, I usually have #4 reserved for a FFYL Launcher and #3 for whatever the Situation calls. I.E. Hornet for Surveyor Bots
Shields are Hide of Terra and Love Thumper. LT is easier to handle and the best to get a feel for melee playstyle, as you at least don’t have to pay constant attention to managing your shield. However, the HoT packs a lot more punch with proper parts and the spike as well as the nova are quite useful. You’ll also won’t kill teammates, which the Thumper will do.
Nades are best as a Shield stripper, Storm Front or Chain Lightning will do a superb Job here. To Clarify: It is to strip your own Shield, as the Roidbonus will only apply when your shields are down.
As Relic use a Bone, Element whatever suits you best, although I’d recommend Corrosive/Fire, either as the situation calls for, or if you don’t want to lug surplus equipment around with you probably corrosive (Buzzards, Surveyors etc).
Class Mods Leg. Hunter is easier to use for general mobbing thanks to the big CD Bonus and the 10% heal. Ninja for the big baddies.
Playstyle is to get fairly close, go into Decepti0n, throw out Kunai, strip your shield if it isn’t down already, down your Kunai’d target (you’ll recover your Kunai that way!) throw Kunai, kill, Kunai, kill etc. until you run out of enemies, or make a mistake to break Decepti0n. Switch weapons (Rapier/Grog) as needed while in Decepti0n, if you get thrown out the Grog/Ruby is mandatory to keep you alive. This is also where Be Like Water shines, shoot, slice, shoot, slice rhythm to keep your target slagged will keep the buff up.
Other Differences in the Build:
While Ir0n Hand and Resurgence aren’t bad, they aren’t that great either, which is why I only invested a point each, to get the respective bonus applied from L. Hunter and L. Ninja.
BLW is more useful to me, as I adopted said rhythm (shoot, slice, repeat) when out of Decepti0n which constantly keeps the buff up and as I’m usually constantly on the move LTW is up most of the time as well, which is equal to a 5 Point Ir0n Hand investment in terms of DMG. The HP boost from Ir0n Hand is not really useful. It won’t save you and it can make gating a bit harder to get done.
Rembember to scout the area where you’re going to execute enemies in for barrels: everytime you connect a melee hit with the Thumper you release an explosive nova and if there’s a barrel nearby you’re dead; with the Hide it’s a bit safer but you must pay attention when stripping it down, too.
Other than that @Maveco’s suggestion is the best I would give.
Go look at a few of StrikerZidane’s videos on youtube… IMO he executes melee zero perfectly, great example.
As long as you’ve got the gear and a decent spec, it’s really straight forward. I had never tried melee and dove in head first at OP8, now I just annihilate things.
here you go, you wanted a pro 
heres another pro, in depth tree and gear guide:
The one necessary requirement that no one has even thought to mention for Zero to release the full potential of his melee skills…you must be wearing no pants.
#######nopants
My dudes been rocking that old school bathing suit ever since the Son of Craw headhunter pack came out, close enough.