CS well. This is the big thing. It doesn't matter what lane you are in, if you can't CS, you are hurting yourself. A full wave of CS is almost a kills worth of gold, so missing those minions will hurt you. Obviously, don't put yourself in danger for CS, but be sure to get the CS that you can get uncontested. You play jungle a lot, so I'm not sure what ideal CS for a jungler is, but for a laner, strive to have 70+ CS every 10 minutes.
Look at what is strong in the meta. Last patch, Caitlyn and Lucian were really strong, so playing those champions was an easier way to climb over playing other champions. If you are good with Elise, for example, she's supposed to be a strong jungler, so learning how to play her might help with your climb. Additionally, she's one of the few AP junglers, which helps with those full AD comps we see a lot down here.
Take advantage of the chaos. I play a lot of Brand support to help cover up the weaknesses of my team. Because of that, I tend to do a lot of damage cause people don't really know how to behave around a Brand. The entire enemy team clumps up, time to ult. Someone is running away with their ally, time to ult. I don't play jungle, but there may be a jungler like that where people don't know how to play vs this champ and thus die a lot cause of it.
Look at the mini map and ping. Very few people in low elo understand how important the mini map is. If you can use your map and try to help your team by pinging while they ignore their map. It may not work, but you may be able to get people to listen to you.
Figure out who is strong and help them. If you have a 5/1 top laner, try to keep them safe. If your bot lane is strong, try to help them. The number of times I'll have a 15/2 Draven or a 20/5 Kog'Maw and our Zac jungler is busy building Dead Mans Plate instead of something like Knight's Vow amazes me. If someone on your team is that far ahead, help them carry. They may not need the help, but it never hurts to make sure your win condition stays alive. Additionally, stay around them. If they are stupidly suiciding, then ignore them. but if they are making good decisions, then stay around them and help them.
Take free kills, don't strive for the outplay kills. Had a game where the enemy Draven was solo pushing top lane, so I pinged him two or three times and started running at him, while the rest of my team ran at the enemy team who was mid. A 4v5 is good, but why not get the 1v5 kill that's basically guaranteed unless we royally screw up over hoping we outplay?
Respect global ults. If there is a top lane Shen, focus ganking him over other lanes because he can't ult himself, whereas if you focus bot or mid lane, Shen can join the fight and counter gank you. Same with Twisted Fate. Pantheon is a little harder, but if you can put him behind, he'll be less hassle later. Additionally, in these games, DON'T BE ALONE DURING LATE GAME.
Understand the strengths and weakness of your laners. Nautilus is a great tank, but he will be a tank regardless if he's ahead or behind, whereas getting a Fiora ahead is really important cause she'll snowball much better if she gets some kills early. Fizz will generally be pushed in early game, but will eventually hit 6 and then roam to get kills. Applying pressure pre-6 might help him survive the weak part of his game, same with Kassidin. Katarina and Draven need to snowball to be good, so help them.
There's probably more but I was trying to think about generally advice, not laning advice since you're a jungler, which is not a role I play.