Welcome to my first guide. As i searched on the internet i did not find any updated Diana Jungle guides and since in 5.3 she was changed this is even more actual. I play Diana since she came out in S2, and i try to show her strenghts and weaknesses in S5.
Diana was a beast when she came out, until she had one of the biggest nerfs of all time starts at 1:36. She got some minor buffs since that and she is slowly getting balanced but the (patch notes) old nerfs still hurt.

Show some love for Diana as she is one of the most fun champions to play.

5.3

Passive - Moonsilver Blade
Now displays number of stacks and remaining duration.

W - Pale Cascade
Pale Cascade's spheres now rotate at roughly double the speed

Small help, but not really game changing.

Pros:

• Burst/AoE CC/Gapcloser
• Teamfight initiator (great w Orianna)
• Q does same damage to all targets, reveals theme for 3 sec (great w slow from Raylai's )
• Strong 1v1
• Strong midgame snowball
• High damage even with defensive build
• Great cleanup, strong against more enemis (2-3) after they blow their abilities in the teamfight with your aoe spelss, and reseting ulti they cant stop you
• Strong countergank
• Fast jungle clear, good sustain you can do almost full clear before having to back
• Good at stealing dragon or baron, (bit similar to Lee Sin) you can ult on the buff than right before you arrive smite it
• Passive scales every lvl, great at late game

Cons:

• You need lvl 6 to use her full potential
• Weak early/late game
• For full burst you have to hit q, if you miss your damage is lowered significantly
• No escape after going in (thats why Zhonya's is essential)
• Need time to auto attack for full burst (ideally you have to aa twice before going in)
  

Blue side: Krugs (smite), Red buff , Blue buff (smite), Wolves, Raptors, Krugs (smite) Recall
Red side: Gromp (smite), Blue buff, Red buff (smite), Krugs, Raptors, Wolves

You can gank before 6, and blow flashes but your priority is to get to lvl 6 ASAP.
Chilling smite is grat addition to her kit.