I really enjoy jungling, im not the best but im good.
First, lets list some jungle champions.
Nocturne, xin zhao, jarvan4, VI, Maokai, olaf, hecarim, shaco and so on.
Lets take nocturne for example, in my eyes he's a very good jungler.
Q good if it lands, leaves a trail behind the enemy as they move which if you stand on increases your move speed.
W is a shield which blocks any spell, for example you come in for a gank on lux in mid lane, she trys to bind you, pop your shield which blocks it and then you gain attack speed
E is a fear after a second or two not 100% sure the exact time, pretty self explanatory why its good.
R now his ultimate is fantastic has an extremely good gap closer, removing vision of the map for the enemys, also good if the enemy your ganking uses flash, use R to catch them.
His passive is great, every 10 seconds your next auto attack deals 120% AD and cleaves infront of you giving a % of damage dealt converted to health.
So jungle, the main aim of jungle is to assist the lanes in gaining kills, also usefull for killing dragon and baron as smite deals a lot of damage to minions, also wriggles lantern deals a lot of damage to minions.
A typical jungle route is, Start wolves, get a smiteless on blue, move to wraiths, kill red buff using smite, kill golems when smite is up again as they deal a lot of damage early on, repeat this while trying to gank the enemy.
If theres any other questions you have just let me know.
/Proxeum