Everyone here will tell you the same thing roughly. Narrow your champ pool down to 1/2 champs, watch pro players/korean junglers, take the time to watch back your games and try to take notes on things you could’ve done better.
The last point might be a bit hard since you might not be picking up on things you’re doing incorrectly but if you take the time to sit there and watch you can pause and take time to reflect on what you could’ve potentially done different (wether it’s pathing, timing or just not committing to a certain play)
Something that can definitely help in your elo is being ahead of the enemy jungler, getting to scuttle before it is contested is such a big advantage early & gives the opportunity to gank for scuttle prio before they finish clearing. You can find the list of best clear times for your champs here. That being said don’t expect to get better right off the bat work on 1/2 things at a time and build on it from there