Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Armour Pen due to him being a AD jungler.
Armour helps with jungling simple.
Attack speed due to his passive and helps jungle faster.
i have the 1 extra AS quint but that's just preference.
defensive stats to help with jungling, getting the attack speed buff.
smite buff for CD
utility for buff duration.
CV helps with your ulti suprising a good combo. helps to spot ganks. helps your team set up ganks.
5 HP pots and cloth armour standard jungle start.
build into a lantern getting razors first.
then AS boots.
then u can start to pick your items but towards either: nashors tooth (25% CD and attack speed), The bloodthirster, banshee's veil (solves your mana problem), sword of the occult if your getting fed i get it for the assists.
if their team stacks armour get a black clever, you will probably max your attack speed out with that item.
Creeping / Jungling
Start at blue buff, using a HP pot straight away, smite around the 650 HP point.
then go to wolves, then to wraiths, the small golems(use smite on these), then go to the enemy jungle and take their wolves, by then you should have smite back and take their blue buff, you should have enough for razors and be level 4. then go back to wolves and you should be level 5 then do red making you six and ready to gank. To gank look for someone on less than 50% HP. if they are hiding in the brushes use CV and ulti them, using your E to fear asap, and Q to keep up and that should insure you the kill.
wait for the minions to line us and Q through as many as possible, your passive should catch a few anyways and your attack speed should fill a bloodthirster really fast