Well to begin a very large amount of how you will run your jungle depends on who you chose to play.
for example. I use to main as Fiora jungle (an single target, assassin type jungler) when i played her i played very very aggressively, like i would use...
move speed quints
AD reds
Armor yellows
MR blues
I would start with Boots + 3 HP pots and take a point in my W first (passive damage and a parry) take both buffs as fast as possible (blue first then red)
Now as far as the early game is concerned Fiora NEEDS that red SO BAD cause she has NO CC.
early game u want to spend as much time as u can ganking your lanes as much as possible, this is because Fiora is a very strong attacker, but still clears jungle camps very slowly
So early game ends and u make good money helping out your lanes and you managed to get wriggles lantern! ya wriggles! Now with that u can ward their jungle (preferably red side) and fiora is strong enough to counter jungle most junglers in the mid game. Dont forget to keep ganking the lanes and helping your teammates pull ahead. if all else fails and your way behind in the mid game, throw some wards in the river to maintain safety and thennnnnn its time to farm your camps.
Now late game is generally when all the teams are grouped and everybody is running all over the place so there really is no ganking or counterjungling, just play smart and play with your team.
Misc tips:
~Always try to counterpick if given the opprotunity
+ enemy picks amumu = you could pick shyvana or nocturn or even fiora
~ If you cannot counterpick or you dont own any counterpick, pick a champion that fills the same roll
+ enemy grabs skarner = you could pick warwick, they both play a tankier roll with great teamfight potential and are not completely reliant on buffs
~ The current meta is tankier jungles, keep that in mind
+ even though my whole explaination revolved around fiora she should not be considered at all a "top jungler"
+ just because this is the meta does not mean it wont work, shaco, fiora, and diana are all assassins that can jungle (i play nasty diana jungle:)) an do well
~Know the buff timers
+Blue/red = 5 minutes
+ dragon 6 minutes
+ baron 7 minutes
~learn multiple styles of ganking
+ stadard rver ganks
+ use the brush on the side of the lane
+ come from tribush if the turrets are pushed and minions are tanking damage
~If your learning how to jungling, take the kills from ganks
+ you will learn how to jungle much faster like this, once you become a good jungler you can worry about how many gp/10 your going to buy and how fed you can make a lane
might add more later idk lulz hope i helped
