For aspiring Jayce players
DISCLAIMER I AM NOT A PRO JAYCE OR ANYTHING IN FACT FAR FROM IT I LITERALLY JUST BEEN PLAYING IT FREE WEEK
Jayce may be one of the harder champions to start playing but after spamming him a bunch and losing a bunch I think I can give a tip to new Jayces, maybe I'll add more to this thread later.
Jayce may have many abilities but his W is arguably the least interactive, think less about using this ability and just focus on actually USING (just pressing W) the ability. It's just stat buffs mostly. For electricity field you can practice getting the AoE on that down and for the Hyper Charge you can practice orb walking but aside from that don't over think it. By doing this Jayce became way less intimidating for me with all the buttons and now I practice to master the stuff.
Also don't be impacted too hard by losses. I get pretty bum'd out being absolutely useless for my team at times at the start but it's part of the learning process. Usually I tell my team that I'm gonna do terrible and beg for getting carried, by doing this you get your teammates to put on their carry pants. Also in general win or loss, if you notice that you're starting to feel more comfortable with the champion you're winning.