Ask your team for a good Red pull, after that take your Blue, go to their Red, Kill their jungle and the red buff is yours, You have to be really fast so ask your team for support.
How to startPurple circles(Buy wards put them in there)
Blue lanes- Ganking lanes
Red lanes- Jungle
Numbers- how to start and where to gank and what to do
If you are starting from another side, do the same (there's no difference a good jungler will not have the problems with sides)

This is a really the best choice for Rengar, you can escape with it or use it to kill somebody.
Another great spell which would destroy their jungler in the start 100% first blood, it will also help you in team fights a lot.
This is a spell that we all used to use on Rengar when he was released, it is a really good spell for chasing your enemies or lane ganking, with your ultimate this spell is a killer combo.
I do not prefer it on Rengar since, it won't be of any use to you, you are a jungler not a laner, it's hard to gank with teleport as Rengar.
Rengar is one of the best junglers in the game if builded correctly and played right, reason of this are his amazing spells.

Why should you rush for this item? Because it will give you insane damage and life steal, it's a perfect item for your Perfect item which will provide you great ganking with your although you can sell it in the late game for Spell blade(sheen) will stack with your and make the damage even more insane, it also gives attack speed and movement speed which does feed Rengar, Phage will slow your targets another great ganking item.
A feed Rengar will need this, because they will focus on you while they kill your Guardian Angel you will have a great chance to escape and also your team will probably kill them and you won't die.
Great item for killing somebody with Armor, mostly used for destroying APC or ADC.
Another great slow effect, and it will give you damage+health.
Another great item for killing their adc or apc.
This item will increase your lifesteal, and when you need to use your to heal up it will give you extra healing amount.
Insane crit which would destroy any adc with 2 hits.

Most problematic person in the jungle would beWhy? He can catch you, and he will deal more damage than you. If you want to Counter Jungle him you got a big chance to fail at it.
One more problem that would end you if you try to Counter Jungle him with out ignite, in this situations ignite is a great spell, it would destroy his passive.

Why should you go 21/9/0?
- Because you are a counter jungler which will make huge damage, you are Rengar which destroys anyone with his ultimate especially their ADCS or APCS, 9/21/0 is not a great choice for Rengar because he is not a tank, Rengar is an Assassin.

Pros

- Brutal Damage
- One of the best champions with focusing on the target
- Easy to trick somebody or escape
- Can heal with his spells

Cons

- Squishy in the Start
- Rengar is being focused a lot

Is the skill for the damage max it first, it will give you great amount of kills.
Max it secound, it will slow your targets and deal decent damage, it will also help you to escape when your ulti is on CD.
Great survivability spell which heals you, it will help you a lot.
Your ultimate, great for escaping, focusing, stealing or

- Ruin your enemies Jungle as much as you can.
- You will destroy enemy team Jungler by destroying him.
- Do as many Dragons as possible, Dragons win the game.
- Buy wards, help your team mates.
- Try to avoid death.
- Always be there in the team fights, never let your team engage with out you, results can be fatal.

6/10/2013 Extended chapters.