Jayce has tons of poke damage and can constantly abuse the enemy before initiating a fight. Try to delay fights while you harass the enemy with your Q.
As Jayce is a ranged champion, you can often bully melee champions down and harass them whenever they walk up to last hit.
Jayce has a lot of utility thanks to his basic abilities. This allows him to help his team out alot and helps them disengage or engage from fights with ease.
He is mechanically a very difficult champion. You’ll need a lot of games to master this champion.
He will run out of mana quickly, so you need to always keep an eye on your mana bar.
If you’re behind, you’re going to deal no damage in team fights and your poke/all-in will not be very good.
0 - 15 min
Once you have a few levels under your belt, you can start to play aggressive and look for aggressive plays. You benefit from extended trades, so try to go for them frequently.
When you hit level 6, you need to play a bit safer as you do not have an Ultimate R, unlike every other Top laner. Play respectfully and stay at max range while harassing the enemy from afar.
Use your Q to poke the enemy as often as possible. Use your basic attacks in conjunction with this ability to get the enemy low.
15 - 25 min
Delay team fights while you harass the enemy down with your Q. Get them as low as possible before committing to the fight.
Split push and focus on farming in the mid-game. Only join team fights when there are no towers left to take nearby.
When split pushing, use your strong duelling potential to fight anyone who tries to stop you from farming or taking towers.
Stick with your team in the late game. Do not split up or walk away from them otherwise the enemy may try to pick you off or initiate a 4v5 fight when you’re away from your team.
Use your Q to harass the enemy as much as possible before committing to the team fight. Getting them low first will make it easier for you to win the fight.
Peel for your carries and focus the nearest enemy champion if you’re weak. If you’re ahead, focus the backline and try to take them down instead.
Jayce doesn't really spike at level 6 due to his Ultimate R from level one. This also means that he has access to three more ability variations than his opponent. He should use them to get a lead pre-6.
Jayce is weak early on and does rely on his E > Q combo to poke enemies out before going for a kill. This will allow him to garner a lead and burst the enemy down once they are low enough.
The first component will give a damage boost to Jayce and will let him play more aggressively. It will allow Jayce to go for frequent burst trades after poking the enemy out with his E > Q combo.
Jayce won't be spiking too hard at level 11 because it won't be giving him as much stats or utility as most other champions' ultimates. It will definitely allow him to increase his overall burst damage, though.
Once he maxes his Q at level nine, he will be able to dish out a lot of damage. This is especially true if Jayce hides in the fog of war and manages to burst down an unsuspecting squishy enemy with his E > Q combo.
Jayce's poke is directly proportional to the number of items and components he has at that time. Due to his ranged stance, he can quickly go for short burst trades where Jayce is guaranteed to come out on top if he spaces well.
Jayce is really good at poking enemies down with his E > Q combo. He can even one-shot targets if he is far ahead of the enemy team. This will allow him to create an advantage for his team before a major fight.
Once Jayce is full build, no squishy enemy target in the game is safe. This is because he can easily blow enemies up with his E > Q combo. Sometimes a single combo is all it takes to kill a target (like a squishy support, for instance).
Jayce won't spike at level 16 either because his Ultimate R won't be providing with him a lot of raw stats, which other champions' ultimates offer them with. He will still have to rely on flanking and using the fog of war to poke enemies down. The greater the number of enemies hit, the better it is for his team and him.