I had to come up with a champion to make my first guide. Then it came to my mind that there is not many jungleguides for Master Yi here on Mobafire. So since I enjoy jungling with him I was like "Why don't let others get a taste of this OP jungler?"
So here it is and I realy hope you will like it :)

In masteries I have focused the junglepart. You get a lot of extra damage on creeps and take less damage from them. Also you get a bit health regeneration for you to stay in the jungle without needing to return home just because of need for HP because that just makes you feel like you lose a lot of xp and gold. Many people says that the Executioner is not good for damage because it only makes a very small difference. I would agree with them in some cases, but as a jungler it's really annoying to "waste" a hit on a creep with 2 HP.

In runes I focused on talking armor and MR pr. lvl runes because when jungling you don't get that many hits on you in the first couple of levels and you don't need the stats. Just when you have these runes try to avoid getting in the center of an early teamfight because you will be very squishy early-game. Wait for level 10, then upgrade Meditate and you will be very less squishy and more able to join the teamfights.

When jungling you don't need meditate. Just buy the 5 pots from start and you wont need healing anymore when just jungling. Your health regeneration will keep your HP up from level 3-4 so that you don't need any pots or meditate. If you want you can just rush your Alpha strike as fast as possible to get quicker farm but remember that you will also need the attack damage bonus from Wuju Style when ganking and in team fights.

I would recommend you to buy Berserker Greaves for the damage as the start of the build will not be giving you so much damage. If you see the enemy team has a lot of physical or magic damage you might consider getting Mercurys or Ninja Tabi. If the enemy team just kicks your *** off and you feel like a feeder, you might also consider to get Frozen Mallet and Warmogs before Phantom Dancer to get some early defense. If doing this I would strongly recommend you to get Berserker Greaves instead of Ninja Tabi or Mercurys because you need to deal some damage too. Also you should rush your Wuju style to get more damage and wait with the ALpha Strike till you got Wuju Style at full. If you see that your enemies deals a lot of magic damage you should at some point switch out your Wriggles Lantern with a Wit's End to get some MR.

As sommuner spells I would strongly recommend you to get Smite. Master Yi might have the possibility of jungling without but he will get at very low HP at the first blue and might have to recall very early.
In addition I take Ignite to ensure getting a kill when I gank. Depending on your team and how much CC they have you could choose to take Exhaust instead for slowing down the enemies when ganking.
If you can't live without your flash just take it. It's a great spell too, but I prefer Ignite or Exhaust.
Some people uses heal with almost every champ. I would recommend you NOT to choose heal with Master Yi. He has Meditate and that's fine.

When Jungling you should do Alpha Strike on the smaller creeps and start with it on the bigger ones. Use Wuju Style on Red, Blue and Golems, but spare it on the smaller ones because the passive will else be gone for the next creeps which is annoying. As Master Yi you would have to start with blue because he uses a lot of mana on Alpha Strike.
When you have got some levels and maxed out Alpha Strike you will get to see how great a farmer/jungler Master Yi truly is. Just by making Alpha Strike on Golems could leave you only two extra hits before they are dead (one if your passive is ready). Also early game keep in mind when your passive will strike next time. Don't use your passive on a creep which only needs one hit (that would just be plain stupid right?)

Since this is my first Guide there is not a lot of pictures, coding etc. because I haven't learnt it yet. I actually don't really know how I get to learn it... If you want to help me with making better guides by adding pictures and codes please leave a comment about it.

PLEASE DON'T DOWNVOTE THIS BEFORE YOU TRY IT. It is a good way to play Master Yi, so read the whole guide, try a couple of times and then you may downvote as much as you will.