You want the wave near your turret, so you can avoid him getting shock blasts from off angles and his hammer form threat. Try not to push the wave when you are farming with q.

3Q>E max Prioritize staying healthy over getting cs, but make sure to always get xp. Stand behind minions so Jayce has a tough time hitting his shock blast on you. Try to play around bushes in the early levels so Jayce cannot auto attack you for free. When he is in hammer form, make sure you are not too close to any minions so Jayce cannot q onto them and hit you with the aoe damage and slow. If Jayce does not have a good back timer and suddenly goes into fog of war, he might be looking to land an empowered shock blast on you.

Do not trade with Jayce early unless he is out of mana. At six, trading is still not recommended since he can get some very positive trades if your spacing is off with acceleration gate into his hammer form abilities. Do not interact with him when he has serrated dirk and tear.