Basically this set up is for people who love to play aggressively. It's all about killing and killing fast. Yes, you sacrifice health and some defence, but you more than make up for it in crazy attack speed and damage. With life steal items you won't even really need much defence or health.

Starting
So you want to start off with the vampiric sceptor. This is for life steal obviously, and you'll want to be able to stay in the battle as long as possible. As a physical attacker, Yi is more prone to take damage as ranged champions can get a few shots in on him from time to time. For this reason you want to start out with life steal so you can heal up off minions and keep earning gold/experience instead of recalling every minute.

Alpha strike as a starting skill is also very useful, in case you get that chance for an early gank. Aside from that, you can get some range with it and not put yourself in any danger. If you target a minion that is close by, Master Yi is still going to hit 4 enemies. So basically he'll be running in, hitting any champions in the area then getting back to a safe distance all in an instance.

Next you want to get Wuju style, obviously for the passive attack damage. Just alternate between wuju and alpha strike as indicated in the skill sequence.

Mid Game
Assuming you've gotten the hang of using Master Yi, you should be doing pretty well for cash by the mid game, even if you haven't scored any kills. Alpha strike is very useful for farming as it'll pretty much gaurantee you 4 killing blows everytime.

Ok, so first off is attack speed. By mid game, you should have the phantom dancers and the beserker greeves increasing your attack speed, movement and critical strike by a lot. You should also be working your way towards the black cleaver, starting off with the dagger for even more attack speed. All this attack speed and crit, combined with Master Yi's ult, is really deadly, and you should really start to be getting some easy 1v1/2v2 PvP kills.

With the high attack speed you've also got a great chance to get the final blow, so you'll be raking in kills and the gold from those kills. In turn this will allow you to buy the rest of your items with ease. Once you've got the cleaver and bloodthirster, you can start taking on multiple enemies alone, easily. Best to start off a fight using Wuju style, then getting close with alpha strike if you are not already in range. Once you've lowered the targets health to about 60-70%, you should be good to turn on highlander and really start dealing some damage. If you get the kill, great, all cooldowns are reset and you can move on to the next opponent for another kill and so on. Good timing with his ulti, means he can just keep on using it, that is how you score multi-kills with Master Yi. However, if you don't end up getting the kill before your ulti runs out, you can easily get in range of the target again with alpha strike. If they're running behind towers or anything, ignite is especially useful for this.

End Game
By the end game, if you've done well and you've got all your items, you're going to be legendary in no time with a DD/life steal set up. You should be able to easily win any one on one and 2 or even 3 on one should not be too big of a problem. Master Yi also does crazy damage to turrets with the attack rate, so you can push through the map, very quickly.

If you've got a good idea of how to use a melee character, you will dominate with this master yi set up.