This is a pretty straightforward build, its a clone of the Wuju style build it is just flipped. I feel that starting with alpha strike leads to quicker last hits on minions and better harassment to your opponents. The main point of this build is for laning in the middle but it works for the outer lanes too, its easier for you to be 1v1 rather than 2v2 with Yi because he is kinda squishy early game.

pros:

good harasser

high damage

high speed

good carry

high crit

cons:

easy to kill early game

burns through mana fast

vulnerable to disables

I chose heal because its always good to have because you dont have meditate till mid/late game. plus its good for late game when meditate is on cooldown and your in a tight spot. clarity was put in because Yi burns through mana fast in early to mid game so its a great tool to use, to keep you from having to port back to by mana pots and recharge. it keeps you in the middle of the game so that your opponents dont get the upper hand.

the best way to use the skills is to be constanly harassing your opponent with alpha strike, most players stay in the lane till they have no choice but to run away. to get kills basically get the player to about 30% health then pop wuju style and smack em with another alpha strike and just follow them till they fall.
something to consider: be sure that you are closer to one of your turrets when chasing, you dont want to get caught by the enemy turret. they hurt a lot.
after you reach lvl 6. use highlander to catch enemies and to lay hits fast in combination with wuju style.

your early game items are boots of speed, health pot x2, mana pot x1. starting to build your boots is important movement speed is more important than AS in early game, it wont take very long to get them. after you get your boots make sure to keep up on your pots though out the game and dont be stingy with the health pots I always try to use them if i get anywhere near 50% health. starks fervor is a wonderful lifesteal item, it also give a good AS boost. buy the recurve bow first, at this point AS is essential to gaining gold faster. your items are very important, Yi's high damage requires items. its best to save up the extra 1500 gold to finis it off. next is the most important item the infinity blade, very expensive but well worth it. work on the AD side first, get the B.F. sword, then buy either of the other two sub items to make the recipe cheaper. Next is the phantom dancer this gives you the last bit of AD and AS you need. start off by getting zeal its a cheap price for the major chunk of this item then save up for the rest. last is the guardian angel, this item is good for the invulnerability thing. its good for when are a few points away from killing someone but die first. it suprises opponents that are trying to get away also.