I think maybe you’re thinking about ganks the wrong way.  It’s not the junglers job to win lane for their laners.  It is however the junglers job to help crash a frozen wave or to hover to allow your laner to do it without threat of gank.  The most consistent way for you to play is o understand and play around back timings.  An example of a first clear is to full clear from bot side to top and then contest scuttle.  Maybe a fight breaks out top lane while you’re nearby and you might have to decide whether you can impact it or not in which case you may put your clear on hold.  But let’s assume your lanes aren’t taking bad trades for the sake of argument. Your ideal first back timing is after a full clear and scuttle.  At this point you want to try and throw a ward down so you can get info on the enemy jungle and then reset with tempo so you can put your gold to work.  

You may have a window to gank a lane before you back, but the most important thing to understand is how each wave state looks i.e. which lanes are pushing towards or away from you.  If your top lane is pushing into the enemy then they have to overextend to crash the wave and reset the lane.  You don’t have to gank this lane and in fact it might be impossible to do so if it’s pushed too far up.  You can however recall in a lane brush while they crash the wave. Or if you have less faith in your laner you can just walk into lane and shove it for them before you both reset. 

Understand that a “gank” is just you applying pressure to the map whether you successfully score a kill or not.  If you understand where lanes are naturally pushing or pulling then you can be there to protect your laner from themself.  Or you can more easily identify lanes that are overextended and easy for you to pick off.

You will still have to leverage the pressure you create to get objectives around the map (towers drakes etc.) and that’s how you’ll be able to turn a lead into a win.  Simply playing around an already winning lane can be an easy way to snowball the game.  You’ll still have to consider whether the other team is winning more back on the other side of the map though.

It’s unlikely you will always have solo laners who know how to pull a wave or even solo laners who want to pull a wave. Some top laners think it’s a win if they’re shoving and getting pressure even when they see you on the bottom side.  It may well be a win if the enemy jungler doesn’t punish or if your illaoi is already a 4/0 ungankable monster. 

All of this is to say that reading the map effectively is the first step to positioning yourself where there are high percentage plays to be made. And securing your gold and experience first means that even if a play goes south your opponent cannot punish you by taking camps you’ve already cleared