Some tips that I have found to make my jungling play a lot more successful:
1. Gank mid often (by camping around and returning to the mid, you have the same access to both top and bot if they request aid or see another gank opportunity).
2. When a gank is successful, don't hang around, jump back into the jungle towards another lane, gaining gold along the way for effective lane presence + successful ganks.
3. Make sure you have great Quint's and runes (goes without saying but very important and game changing if done correctly). I prefer Gold production quints + heart of gold + phil. stone + blue sword thing (+5 gold/5) + gold production in utility mastery = NEVER having gold production issues, in fact you will find that you will complete your build and have too much gold this way sometimes.
4. Use champs with great mobility to allow you to traverse the map better (personally I like Sejuani and Malphite a lot because they can quickly rush through walls--rediculously relevant and highly overlooked in the jungle) Yes, Malphites ultimate does go through virtually every wall = OP jungling gank madness!! Also, try to get champs that have great cc, that is important beyond measure (try Nunu, Sejuani, Amumu, etc). Nautilus....Oh friggin Nautilus as a jungler.... friggin nightmare!!
5. Try different builds and see what works better, don't be scared to try things that don't work in ai bot matches or something.
6. Make sure you have relevant summoner spells (in other words, don't always go smite flash because its whats run all the time. I use clarity with Sejuani, Malphite, and Nautilus and have noticed significant increases in my jungling gank success rate.
7. ALWAYS BUY WARDS!!! NO EXCEPTIONS--YOU ARE THE JUNGLES SIGHT.
8. Don't hog all of the buffs for yourself, pull your Mid AP and give them blue, or your main AD give him the red, this will help your jungling more effectively because you will have stronger teammates to complete ganks with.
9. If there is no counter jungler, eat away at the enemy teams jungle like a monster (I have pulled some crazy ganks that people didn't expect because of this).
10. When counter jungling, ward their blue and red often, and gank them within their jungle, bring a friend and laugh about it--it's fun!
Anywho, hope this helps--this is kinda like a top 10 for me, and it has helped my game loads--I hope it will help you out friend. Good Luck!