Jinx will use the extra range from her Rockets Q to poke you down and push the lane. Make sure you’re outside of the minion wave so she is unable to deal splash damage to you or the minion wave.
As a carry, Jinx is very dependent on others to assist her in snowballing. Try your best to take advantage of Jinx when she is in the lane alone.
Jinx is rather defenceless outside of her Flash when her E is down. If she uses her E, try and exploit her weakness and use the long cooldown to go for another skirmish.
Jinx doesn't have much help in the mobility department. If you or your team lands any crowd control on her, it should result in a kill. Try and lock her down as quickly as you can so she is unable to “Get Excited!”
In team fights, avoid grouping too close together as it will allow Jinx’s Rockets Q to deal lots of AOE damage. It will also make her Ultimate R less effective if you’re slightly split up.
When taking objectives, make sure you’re not low as Jinx may be able to take you down with a well-timed R. She can also steal objectives like the Dragon or Baron with her Ultimate R, so make sure you finish the objective off with Smite.
Once Jinx gets her core items (Infinity Edge and 2 Zeal items) she will be pumping out DPS in team fights with her rockets. When trying to team fight, engage as soon as you spot her- do not let her auto-attack for free in the backline.
At level 6, Jinx’s Ultimate R can be a great trading tool and it can turn the tide of the lane. If she is not using it in her own lane, she might try to secure kills with it in other lanes with it. If you see her use her Ultimate R and it’s headed topside, ping your team.
At level 9, Jinx’s auto-attacks will deal lots of damage as she would’ve maxed Q by then. Keep this in mind and avoid fighting her alone as she is good in extended trades.