Jayce is a pretty versatile champ that could pretty much do anything. His jungle is fast and his solo lane is amazing cause of his farming ability. Play Video

Pros.
Can do any lane
Great with ganks
OP cannon
He is Mellee and Ranged
Kinda Tanky
Cons.
Starts off weak
Will suck if you don't know what your doing

When Jayce is farming top it is really easy because of the fact that you could harass without taking much damage. When a large group of minions is coming at you,(Starting with Mercury Hammer) you could start by jumping in with your Q where you will be right in the middle of the action then your W to damage the rest of the minions and if any other champs are coming at you you could hit them back with you E while you can continue farming. Or (Starting With Cannon) You could farm from long Range by maxing out your Q And using your Acceleration Gate for the bonus Damage and Range. When your low on man it is best to farm with your Mercury Hammer because the passive with your hammer's W you get man for eat hit.

Jungling(Watch in Hq) Play Video

To start off ganks Jayce can use his Acceleration Gate while shooting his Q for the initial Damaging and while the gate is still in effect if your team mates run through the gate they have increased moment speed. Jayce could also single people out with his hammer, while using his hammer upon switching between weapons he avoids running into minions or champions so he could separate any enemy champ by pushing them away with his hammers E
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Buying Boots of speed and 3 health potions is normal for any champ for the beginning of the game. Buying 2 Dorans blades gives your the ability of farming with lifesteal and a little bit of extra health in the begging. After buying The B.F sword His abilities will have more power since most of it depends on damage. I chose the Black Cleaver Because Jayce Has long Range ability and thePassive to switching to his cannon is it decreases the enemy's armour so with the cleaver it lowers it even move and while switching to your hammer you also deal bonus damage to the first hit while you single them out with your E

His Mercury cannon used correctly could single anyone out even if they are at a turret or little health, using the acceleration gate and his Q the damage could be dealt from very far away