Hi! I'm Avian657 and this is my Jayce guide!

Jayce is sort of an odd champion. He can be bashing peoples faces in up close or firin' his lazar from afar. So, if you like doing either one of these, Jayce is a champ for you!

Pros Can play either range or melee Can deal insane amounts of damage with Shock Blast and Acceleration Gate Passive gives a speed boost When changing to and fro hammer to cannon, gains extra abilities on next basic attack

SPACE

Cons Need to know right timing to switch from hammer to cannon Passive doesn't give much of a speed boost Not much CC with Thundering Blow

AD Carry masteries. Nothing too special.

These runes are pretty self-explanatory.

In Build 1 I've chosen the Greater Quintessence of Attack Damage and the Greater Mark of Desolation to maximize the damage you do. I've also chosen the Greater Seal of Armor and the Greater Glyph of Scaling Magic Resist for the armor and magic resist bonuses so you're not as squishy.

In Build 2 I had to give some thought to this... Should you be able to wipe the floor with your opponent or should you make it so they cant touch you? Since Build 2 is going more on the tanky side of the spectrum i chose the Greater Seal of Armor, Greater Glyph of Magic Resist, and greater quintessence of vitality with the greater mark of desolation to give a little more oomph in fights.

Hextech Capacitor(PASSIVE): Jayce gains gains 40 movement speed for 1.25 seconds when he changes form of his weapon. This has some benefits, but not much, considering the amount of the movement speed bonus and the amount of time you get the bonus.

To The Skies!/Shock Blast(Q):
To The Skies!(HAMMER) Jayce leaps to an enemy dealing 20/65/110/155/200 physical damage to enemies and slowing them by 30/35/40/45/50% for 2 seconds. Great if you need to cover distances to smash peoples faces in.
Shock Blast(CANNON) Fires an orb of electricity that detonates upon hitting an enemy or reaching the end of its path, dealing 60/115/170/225/280 (84/161/238/315/392 with Acceleration Gate) magic damage to all enemies in the area of the explosion. One of the most overpowered skills I've come across in LoL. It naturally deals massive amounts of damage and can deal even more damage when it passes through Acceleration Gate.

Lightning Field/Hyper Charge(E):
Lightning Field(HAMMER)Passive: Gains 6/8/10/12/14 mana per strike while in Hammer Stance.
Active: Creates an electric aura dealing 100/170/240/310/380 magic damage over 4 seconds to nearby enemies.
If needed, you can switch to hammer form and restore some mana if needed. The passive AoE damage can be used as a pretty good farming tool
Hyper Charge(CANNON) Jayce gains a burst of energy, increasing his attack speed to maximum for 3 attacks. Each attack deals an additional 70/85/100/115/130% damage. At max level, if your playing AD, can really hurt.

Thundering Blow/Acceleration Gate(E):
Thundering Blow(HAMMER) Deals 40/70/100/130/160 plus 8/11/14/17/20% of the enemy's maximum health as magic damage and knocks them back a short distance and stuns them.(200/300/400/500/600 Maximum Damage against monsters) Jayce's only source of CC. You can use it to knock somebody into your team or simply to try to run away from somebody.
Acceleration Gate(CANNON) Deploys an Acceleration Gate for 4 seconds, increasing the movement speed of all allies who pass through it for 3 seconds. This bonus fades over the duration.(30/35/40/45/50% movement speed bonus)
If Shock Blast is fired through the gate, the missile speed and range will be increased, and its damage will increase by 40%.
Can be used to give a movement speed boost to your team or to **** up your enemy's faces when used in combination with Shock Blast

Mercury Cannon/Mercury Hammer(R):
Mercury Cannon(HAMMER) Transforms the Mercury Hammer into the Mercury Cannon gaining new abilities and ranged attacks.The next attack in Cannon stance reduces the enemy's Armor and Magic Resist by 10/15/20/25/30% for 5 seconds.
Mercury Hammer(CANNON) Transforms the Mercury Cannon into the Mercury Hammer, gaining new abilities and gives 5/15/25/35 bonus armor and magic resist.
The next attack in Hammer Stance deals an additional 20/60/100/140 magic damage.
Changes the form of your weapon to either melee or range. You can use this ability at level 1 so don't panic about not being able to use it until level 6.

These are my items for the AD carry build. The usual AD carry items. You don't have to follow the exact item sequence, just make sure you get these items by end game.
This is obviously more tanky. The boots here are more conditional, you can take either Mercury's Treads or Ninja Tabi depending if the opposing team is either AP heavy or AD heavy. The same goes for the Guardian Angel, it can be replaced by a Quicksilver Sash

LANING

When in lane, no matter what build your using, [color4=red]YOU ALWAYS WANT TO BE FARMING![/color] There are no excuses! If your top, your Lightning Field and its large amounts of AoE damage is an extremely good farming tool. When playing an AD Carry, your support should not at all be taking farm unless absolutely necessary (holding a lane when your dead or buying items)

TEAMFIGHTS

This is pretty much common sense right here:

Here is a list of all of my changes to this guide!

[6.14.12]Guide published completely by accident when trying to save!
[6.15.12]Added items section.
[6.25.12]Guide finally completed!
[7.5.12]Changelog added.

I'd like to thank you all for reading this guide! Please vote depending on how you feel about this guide and comment to tell me what I need to improve on.

I'd like to give jhoijhoi for teaching me how to make a guide and for the dividers!