Jungling in Low Elo is laughably easy if you know what you're doing, you're just not doing it right. The thing about low elo is that laners are very predictable and don't ward properly or just don't pay attention to the map in general. In High Plat/Low Diamond, the majority of laners understand not to be aggressive if you don't know where the jungler is, and they can pinpoint the general area he's at on the map most of the time, but Silvers don't have this level of awareness. This is something you punish through lane ganks, ganks through tri bush, and counter ganks.
If lack of damage is your problem, pick Vi, J4, Rengar (pretty bad jungler rn, better top laner), Kha' Zix, or Lee Sin. Everyone of those champs, excluding rengar, have very potent ganks and can snowball out of control and all build Warrior, giving you an early spike and lots of damage.
Also, if you're team isn't helping in a gank, that means you screwed up the gank. While it is Silver or Bronze and nobody knows what they're doing, Silvers at least have the awarness of not letting a wave and a half to crash into tower, tank it all trying to run up to you halfway across bot lane or top lane, only to burn flash or get counterganked in the process. Ganks are all about TIMING, not mechanics.
This is exactly why on my smurf when I get autofilled I play brand support and run across the map getting kills everywhere, because I know how to time ganks and I know exactly what a laner without a brain is gonna do at any given moment.