Hey, so as you know, Diana is a new champion. This build is only for jungle Diana. It will help you gank easier. At the beginning of the game, if you have HARD LEASH from your friend, you can easy gank the enemy at lv 3. However, if you dont have leash or a bad leash, it might cause your Diana can't gank till level 5 or 6. Diana is NOT a lv 2 ganker (which mean after blue), because when she reach lv 2, you can get your E, but then you have no dmg, which going to make it super hard to gank, and it might cause the death of you or your teammate).

With these Runes. It maxed out your ability in early game, also make you more tanky cause of ganking.

Of course, she is an AP champion, so that will make 21 point go straight to offense. Now, talk about the other 9. I put 6 in defensive, because Diana need armor as she jungle, also with more damage on monsters. The other 3 point on unity will go to mana, because Diana is a caster more than a AP carry. Yes, she will jump to enemy and do normal attacks, but 80% of the time, all she do is cast spells, and her skills cost quiet a bit of mana if we use it continuously.

All champions need a good build to become OP. So, as jungle Diana, the 1st item she really need is sheen, because she will use her normal attack after her cast spell most of the time (especially after lv 6, when Diana have ult.). The next item is Rylai's, it will give Diana quiet a big amount of abilities and a decent amount of HP (can get you to about 2k HP in mid game), you will need this because Diana is a "meele AP", she will need to have more HP or else will be shut down right away. Next, i guess Deathcap is familiar to every single AP champions. Deathcap is a MUST HAVE item for Diana, because 3 of her skills is magic base, and Deathcap always the best item if you seek for OP AP champion. Then grab a Void Staff if the enemy team have a supper tanky champions. Then just finish your build with a Lich Bane since you already have Sheen!!! (Most of the time the game will end when you have Void Staff)

-For jungle (early lv before 6)
lv 1, you grab Diana's W, then get Q. After that, Hit Q before you fight the monsters, then turn up your W, then keep spamming Q and W till monster dead(Or Smite). Repeat this sequence until you reach level 6.
-For Gank (level 3-5)
At level 3, now you can gank since you have your Q W and E. You start the fight with Q, then run to the enemy champion and normal hit ( Turn your W on right when you run in the fight). When your enemy turn around and run, you use E to pull them in again to secure the kill.

-For Jungle (lv 6 and up).
Now, you surely will have your ult. You don't have to stand in front of the mobs any more. you can stand anywhere close to the mobs, then Q. After Q, you can just ult (R) to jump on the mobs. Then turn on the shield, and repeat the Q,w,Q,w combo (or smite on time).
-For Gank (lv 6 and up).
You will also start off a fight with Q, then jump on the enemy with your ult (R). Then your ult will reset (this will come in handy later). Then, turn on shield(W) and normal hit (Q when the CD is down). When they start to flee, press E to pull them in, also slow the enemy. After the slow, if your enemy still super fast and you can't chase, use your ult again now. You will catch up to the enemy and finish him/her off with ur Q and W.

Smite: It's a no question thing. If you jungle, you need smite.
Flash: You need it to escape squishy situation, rescue teammates, secure kills.