I'm a JG one trick and I kind of understand where you are coming from, with this..... from your profile you seem to one trick Diana and play only Kha'zix in the JG. With Kha'zix you need to know that you have very high kill pressure. This means that one or two kills could potentially be the end of the enemies ADC. I'll give you a few other things as well:
Ganks
There are 3-5 gank paths that can be used for any lane.
- Walk-in entrance gank (general river to lane gank),
- Lane gank (walk behind your turret into bushes)
- Backline gank (where you enter from behind the enemy team
- Teleport gank (pretty self-explanatory)
- Counter gank (gank a lane that is in the current motion of being ganked by the enemy jungler).
A gank never has to be successful, champions with high mobility, easy escapes and hard CC can make you fail a good gank. In this situation your only objective is too be painfull for the enemy laner so your laner can do what is needed. Things like walking into a bush will force the enemy laner to hang back while you could be recalling to base.
Vision Control
This is pretty self explanatory, vision is probably the most important aspect of playing Jungle and has a priority over everything. Lets be real if someone is dying in mid lane don't make the escuse of "I need to ward" just run to the lane and but pressure on the laner until they give up.
"If the enemy already spotted me cus my trash laner cannot control the river vision, then the gank a fail already basic knowledge" - This is the worst excuse for not ganking a lane. Realistically you should have wards on you and probably 2 control wards as well. The enemy laner is more likely to be focused on their CS then focusing on the map so you can play a control and gank (DO NOT DESTROY THE WARD UNTIL YOU HAVE COMPLETED THE GANK ELSE THEY WILL KNOW!).
Place deep wards. This is what a genrally do in my ranked games, I place normal wards around objectives, near lanes and in the enemy jungle which then I place control wards behind major objects. Example baron bush top side near pit / raptor camp. I also place control wards where there are wards to obviously deny vision.
Placing wards will help you identify where the jungler is and if ganking a lane you can support them or take drake or another objective. Force them to think they made a really stupid mistake.
There are other things I can say but I can not be bothered. If you need something just ask.
Last topic because im lazy Pings and Map awareness
I can not count how many times I have literally deleted the game and lost my mind with this mechanic. THIS IS IMPORTANT. In relation to ganking lanes ping that you are going in or ping be carefull so you can sucessfully pull off ganks or claim objectives. If your team mate isn't listening to you like in low ELO, throw pings right on top of them so they know. If you are good enough you should win.
If mid lane roams bot or top ping it. Your laner is most likely useless so do it for them and if you know they are heading near you, counter gank them.
Ok I can't be bothered :P, hope this helps. Try not to harass your team mates I understand the feeling you have when your team mates are useless but you have to deal with it like I do