Rangar is a great stealth unit if handle correctly, he can jump in unseen scaring the **** out of the enemy and finish them off fast.

You will be in great need of your Q spell so we will max it first, this spell helps you deal a lot of damage over short time helping you gating the kill, with the first strike dealing ton of damage and the attackspeed boost helping you finish.
You will need the other spells ready so thats why you will take them all in the start, Rangars Ferocity will stack up faster if you have them all and they will com in handy when helping you dealing damage, not to mention slowing the enemy down for a easy kill.

Jungling with Rangar with this start items can be really hard so thats why you have your health potions to help you heal between the first monster kills, i recommend starting with rats(ghosts) getting some help is possible so you not lose so much health and then go to red with pull help and some damage support to finish faster, then go to wolfs and then kill the goloms, in lvl 4 or 5 you can start ganking the easy targets, then in lvl 6 with your ulit you can start ganking free where needed, keep in mind that you shoul not use the ulit if not needed, if you can jump from the bush thats much better because you can use the ulit later if the target gets away to jump in on him/her again.