First, I recommend everyone do this. Jungle is the only role that can be anywhere on the map in laning phase, and understanding what they do and why can stop you from tilting and even open your eyes to the possibility they are doing their best with their given resources. Anyway, here's what I've learned:
1. The Jungler needs you just as badly as you need him. If you have your lane shoved in, and see your jungler nearby, especially in river or enemy jungle, path toward them, even if you only end up walking partway before you have to return to lane. You have nothing better to do in lane other than watch the enemy laner farm under tower, and it is an opportunity for deep vision because you have the strength of two people walking into hostile territory rather than one. Not to mention, if you run into someone along the way, it is often a free kill.
2. If you regularly pick a champion without reliable CC, don't expect a gank unless you have perfect wave management, and stop complaining about it. We can't help you. Even Nasus Wither is often good enough, but if you're picking Illaoi and can't get the wave to stand in a good place, you're out of luck.
3. If you're losing lane, you can be helped. If you play safe and save your CC for a jungle gank, and you avoid pushing, you can be helped. However, if you're feeding, getting solo killed etc., you usually cannot be helped and your goal is, at this point, to build safely, farm where you can, and avoid giving up more kills. Your goal is NOT to make risky plays to gain a comeback unless EVERYONE else on your team is behind and the only option is for SOMEONE to do SOMETHING.
4. Sometimes, there are just better options to gank. Yes, Nasus top may be a gankable lane, but I'm going to camp the Draven Nautilus lane, thanks. I'll still gank your lane, but you need to manage your wave around me, because I'm optimizing my clear around bot lane. Your wave needs to be in a good place when I'm clearing my top jungle near you.
5. Top lane is a hard lane to gank. Not in being difficult to execute, but being top means you're not around for the Drake play. Optimize your picks so that you can win lane alone, and consider ganks a bonus. Pick safely if you pick first, and counterpick if you pick after your lane opponent.
6. Mid/Jungle are just as reliant on each other as ADC/support. A midlaner that does what I mentioned in item 1 is my best friend, and in turn I'll get you fed. The team with river control is the team that gets Drakes, herald, scuttle, and ultimately, baron, and has better control over gank paths, and if I am trying to secure that control alone vs. a jungle/mid that do it together, I will lose, and we will lose the game. As a midlaner, play around your jungler.
7. It is nearly as important for a support to do these same things, and perhaps the only reason it is more important for mid is because they can rotate in two directions instead of one.
8. The jungler cannot be everywhere. They enter the game with a gameplan and priorities, same as you. Just because you aren't their priority doesn't make them or their decision to prioritize another lane or objective bad. It also doesn't mean prioritizing you instead would be a bad option. There are just differing play styles and game plans among all junglers, even in Challenger, the ELO that is most optimized for efficiency.
9. Ganks are usually incredibly easy to predict, and the reason they often work is just because you are so intent on getting that wave shoved before you back that you ignore how bad your positioning is and your lack of vision. Three minions does not justify a death.
10. Junglers that clear away from Infernal Drake are trolling. Junglers that gank top with an Infernal up when they are level 7 are trolling. Junglers that invade the enemy top jungle with Infernal up are trolling. Other drakes apply here too, Infernal is just the most snowbally one.
11. The jungler should not engage the fight for a gank unless you have a gap closer and they have reliable CC. Otherwise, the jungler should be showing themselves AFTER the engagement has begun. DON'T expect them to run in solo when they're a lower level (bc jungle) just to get turned on.
12. Laners need to try to secure vision control in strong gank paths near their lane. It means you can't be ganked easily, and I can gank for you more easily.
13. It is worth missing the wave shoved under your tower to follow up on my gank. If you're shoved in and I gank just to have you ignoring me, I won't visit your lane again.
There are tons more items I can bring up, but the goal here was to tell you how to enable your jungler (with my slight rant about junglers ignoring drakes because it's a pet peeve). If you can enable your jungler, they can enable you. At the end of the day, the jungler can often be looked at as a second support during laning phase. They cannot do a lot by themselves, but helping them will allow you to do more than either of you can do alone. They cannot and should not be expected to carry the laning phase.