Hello guys! This is my first build ever to be made. This build is mostly inspired by TSM Dyrus, but you can't just follow a build step for step. I'll explain this later on.

Jayce is a melee/ranged solo top laner in my opinion. You can build him really damage heavy without loosing the teamfights because of his poke, and you'll escape with your movement speed much easier.

Any feedback would be great. Telling me what I should improve on helps me out. This build is currently being worked on, I'm too lazy to finish it in one set.

Runes are pretty important. I mainly run the runes as I've suggested in my build, but there are some that works good aswell.

Armor pen does good against tanky champions like Malphite, but Attack Damage is great overall on Jayce.

Magic resist per level is also something I recommend looking into. It makes the late game easier, but if you're against someone like Vladimir, you should go flat Magic resist.

Items, the great difference from bad players and good players.

There are some items I find a MUST on Jayce now. The Black Cleaver and Muramana. Those items make a great difference in lane and when poking.
Here's some other items I recommend:

Trinity force: An overall good item on Jayce. The slow from Phage, the Sheen proc and movement speed from Zeal. Health, damage, mana etc. Tons of damage! - Phreak

Last Whisper: Armor pen isn't only good against tanks, but against the squishy people aswell like the ad carry. Most ad carries get a Guardian angle, but with your Black Cleaver and Last Whisper, The armor will be useless against you.

The Bloodthirster: Lifesteal and Damage, what more do I have to say?

Guardian Angle: Armor, magic resist and an extra chance of surviving. Great!

Sword of Divine: This item can turn so much around. I highly suggest you to pick out the ap or ad carry with this item, but it may also be used to save your adc from dying to the enemy bruiser.

Ninja tabi, merc treads and boots of mobility:
Go Ninja tabi if you're against an ad champ and you don't need the tenacity. This also against ad carries.
Merc treads when you're against ap champ or you need it because of their cc. This helps against ap champs.
I usually go boots of mobility when I'm dominating my lane, or if I am just poking at them. Keeping up the movement speed is great.

Using your Acceleration Gate, and then firing the Shock Blast makes it easy to dodge. But there's also another way to make it fire through it faster. Use your Shock Blast and then put the Acceleration Gate infront of the blast to make it hard to react to. This is a simple trick used for poking.

Allways spam your ultimate while going to your lane. It'll give you speed boost every time you change form.