I made this guide because, well for one I wanted to try making one, but also because I see it used very little but I happen to think it works very well. As Phreak said he can be an AD carry or a more tanky character but I think bruiser is probably Jayce's most effective role due mainly to his Mercury Hammer's E. This guide focuses on solo top, bruiser Jayce. This guide is very basic, I'm still getting used to everything but later on I will come back and add more and edit it.

For runes I take flat armor penatration marks for getting that early damage through because, chances are, you will be facing a tank in the top lane more often then not,which means, armor and magic resist.
Next, I set up flat defense and magic resist glyphs and runes because Jayce will be in crowds a lot and he won't need as much ad to get his damage out.
Finally, I get flat ad quints. I know I said he doesn't need the ad but its good to have, mainly for early game burst and pushing your lane.

I won't spend too long on masteries because many people build them special anyways or simply overlook them. I take masteries mainly for damage and some defense. I do this, again, mainly for early game which is when it matters most. Later they are still useful but their effects are lost in the mass of items and chaos that late game brings.

For items I mainly choose tanky items, obviously, but taking a blood thirster right at the end for a bit of extra burst. Several of the later items do add some dps and thats because of Jayce's passive on his E;because, I rank W last so the mana regeneration isn't as effective so getting dps late game can help with mana troubles (you will have some mana troubles, Jayce has low mana costs but drains the bar fast) as well as adding to your damage in team fights.

I pick my skills in this order, because of how the average game would go. I start with Q because the slow from the dive can help early game if your ganked or your defending a buff and a team fight breaks out;also, the ability to have a ranged nuke early on can help poke or check bushes earlier.

Next I get E, I take it because it can provide massive poking power in combination with your Q, help you out of a sticky situation and save your life, or help push your enemies into your turret if your getting pushed. This also provides a massive buff to the cannons Q and can destory the hp of most of the minions early on.

Last, I take W for mainly its mana regen. I never use the cannons W unless I'm pushing a turret. This can be used with your Q in order to wipe out minion waves quickly or simply add to your sustain.

As far as attacking, I stay in cannon mode for most of the laning phase and poke the enemies when I can. Whenever they start to push forward, as long as most of the enemy minions are gone, its best to quickly swap to the hammer, you then use Q to close in on the enemy and slow them down. Now if your simply poking, smash them away with W and activate your W to farm the minions. If you are trying to stop them, activate your W during flight and try to walk around the enemy, when your in the best posistion you can try to knock them back with E. If they are low but getting away, activate your cannon and use E with Q for massive damage and that extra range if they are getting too far.

For summoners spells, I mainly take ignite and flash for escaping, catching up, and picking up kills. These really help to shut down enemies fast or to knock single targets into your team.

Other good spells are Ghost if you want to rely on your own damage and chase, exhaust to add that extra slow for a chance to use the hammers knockback, or heal if you would rather be more passive and need a bit more sustain.

All in all, Jayce isn't as well rounded as everyone would like to think but he is a really hard hitter when you use him right. He has the best buffs, debuffs and passives of any champion ,in my opinion, with two speed boosts, a knock back, a slow, a mana restoration passive and three AoE attacks. He can do massive damage, save his team, and single out enemies for kills. Again, this is a basic guide and I will edit later on as I figure out more and more. As the player improves, so does his stratagy. Rate and comments please. <3