Master yi is good champ for new players. He is cheap, he is easy to control and deadly as hell. He will get you fast ip to buy other champs.

you must begin with the tank, for fist kill, after that you almost wont be any laning.
First start with boots of speedand 2 health potion, with your wuju style and armour penetration runes you do around 100 damage with att speed of 0.8. that is a guaranteed 1st kill. stay in lane until you are lvl 3 and have at least all your skills.
go back to finish your berserker's greabes.

now go mid, kill and do some damage to tower. stay there untill you reach lvl 6. go back and buy vampiric sceptarand B.F. Sword. If you dont have the money for bf, go jungle with your lifesteal. Untill you can buy bf.

now we can get some crit. go jungle lane whatever you want. make sure you keep killing and get money. buy a zeal, and those 2 cloak of agility now you have 50 % to crit, and almost unbeatable one on one. finish your phantom dancer and infinity edge.

the rest of the build will almost never happen because the game is already finished,. because they surrender. but if they don't get an other pahntom dancer and the bloodthister.

then you have one slot empty buy yourself some [frozen malletor thornail depends of the other champs. if they have a tank buy health and if they have a other dps buy armour.
when you have all of your slots full. sell the boots and buy the armour or health you didn't buy yet.

not that you will ever manage to get these items the game is already over.

laning Early game
Wait till you get your dubble blow(your passive skill) pres wuju stylethen alpha strike the enemy champ and double blow him. you now done almost the half of his health just finish the rest.

use all of your skills, also meditate. not for the healt but for the armour.
stand in friendly turret range with low health so the hungry types will attack you. then go meditate and he can't do any harm to you and the tower will kill him. but make sure you hit him once otherwise you dont get the kill. do it with alpha strike for last hit if he runs away.

laning late game
there won't be any. just kill minions to get money and go gank again.

ganking
Wait till you get your dubble blow(your passive skill) pres wuju style, then alpha strikethe enemy champ and double blow him. Chase him with highlander. He will be dead if the low healthed enemy runns away just out of range of alpha strike, use alpha strikeon a enemy champ or minion and 80% of time you still reach him and kill him. farming just keep killing, minions champs monsters doens't matter what just kill. you need the money. use alpha strike frequently. team fights don't just don't!! walk / run away even use highlander for it. they will focus you and you will be dead in a sec. go kill some minions / backdoor / jungle untill a few champs have died and have the half of their health/no mana. Then go for the ks and finish the enemies. low healted fist. And if the friendly champs die they have a backup so the enemy can't push. Go tower hugging with meditate. solo doesn't matter what you do he will be dead. if it is a tank with armour ,. run away. if anybody has thornail just forget it and run leat your teamates do it.[code]highlander. He will be dead
if the low healthed enemy runns away just out of range of alpha strike, use alpha strikeon a enemy champ or minion and 80% of time you still reach him and kill him.

farming
just keep killing, minions champs monsters doens't matter what just kill. you need the money. use alpha strike frequently.

team fights
don't just don't!! walk / run away even use highlander for it. they will focus you and you will be dead in a sec. go kill some minions / backdoor / jungle untill a few champs have died and have the half of their health/no mana. Then go for the ks and finish the enemies. low healted fist.
And if the friendly champs die they have a backup so the enemy can't push. Go tower hugging with meditate.

solo
doesn't matter what you do he will be dead. if it is a tank with armour ,. run away.

if anybody has thornail just forget it and run leat your teamates do it.