I was platinum season 3 and 4, reached diamond this last season (5) and have been placed platinum 2 after my provisional matches this season (6). I have mained jungle for some time now, but also play other lanes when jungle is taken (most of the time support or mid).

Jungle is a very important role during any league of legends match. While yes other lanes may roam to give assistance to their team; it is the sole purpose of the jungle to gank and assist lanes so the team can push ahead in kills and objectives. Finding a good Jungle Pattern is important to learning jungle and the aspects that go along with it. With this build it is a little less important because you are not stacking a devourer or anything like that, but try out some different patterns and find one that you like. Another important facet is understanding when to gank. Lanes may blame you or complain and pressure you into ganking...DO NOT DO IT... It is important to help lanes in need, but not at the risk of setting yourself as well as them further behind. Learn to gauge when is a good time to gank and when you should wait. This is perhaps the hardest part about jungling because lanes that are pushed under tower are still sometimes good lanes to dive for kills while other times the enemy champions under tower is a triple or double kill mistake waiting to happen.

Early game Vi is at her strongest. Once you have cleared your two major buffs and one other camp you should have level 3 and can look for a gank. Make sure your laner is aware of the gank and I would highly suggest smiting raptors for the oracles buff as many like to ward at around 4 minutes which is where you should be looking for this first gank. Harassing lanes early game is a good way to get ahead while you have your blue buff. Vi is also a great 1v1 champ so looking at invading at 6 or pre 6 is a good idea. Make sure you are taking a camp or two between ganks to keep up in level of soak XP off a lane you just successfully ganked (This means the enemy backed or died, don't put your laner behind.)

Vi during the mid game is still extremely powerful and getting ahead now is crucial as she does fall off a bit in the late game. I would stress ganking every time your ult is up for easy kills. Look for team gank possibilities and land those Q's. Shutting down their jungler should be easy, but I wouldn't suggest going into their jungler without flash and ult up as sometimes it gets a little messy.

At this point it is important to not get caught out. Vi is extremely powerful in 1v1's due to her high damage from her (W), but lacks a whole lot of AOE burst you get from other junglers. It is crucial to only fight with the team unless you are fairly certain you can pick someone off in a 1v1 or 1v2 and get out alive. Vi is great in team fights for flanking and taking out a carry and if built tanky can stay in the fights to support the team with peel and some cc from her Q as well as small AOE damage from her E.