You rush Hextech Rocketbelt #1, Liandry's Torment #2.
You get Cosmic Insight rune to use Hextech Rocketbelt more often.
You poke with Hextech Rocketbelt and First Strike to earn gold and burn enemies.
After core items, you adapt. You can play as a tank or as a damage dealer.
How to play
General
Use Hextech Rocketbelt active to poke your enemies all the time, earning gold with First Strike.
Adapt to the enemy team. Build tanky or more damage. You can play as a utility tank, poke, or even you can go some AD items to still have plenty of damage. Depends on the team and how you want to play.
For utility tank, remember that Liandry's Torment works good with Serpent's Fang (to counter shields) and Oblivion Orb (to counter healing).
Cosmic Insight reduces the cooldown of all active items, so Zhonya's Hourglass really works well with this build.
Wait for the First Strike and proc it with your combo, to deal damage and earn gold.
Be careful to not get poked, because you waste First Strike procs.
Your main combo is First Strike + Hextech Rocketbelt + Q + E + E. You can use R to go full in with Ignite as well!.
Your alternate combo just for poke is First Strike + Hextech Rocketbelt + Q and run away. Or even E minion and run away.
Tips and Tricks
Champion
QFlash combo: You can do Vault Breaker (Q) (can be done in any direction), and at the very end of animation you Flash into an enemy.
Riot
A fully charged Vault Breaker will deal double damage. It's great for catching and finishing off fleeing enemies.
Relentless Force does full damage to anyone caught in the shockwave. Use it on minions in lane to hit enemies hiding behind them.
Cease and Desist is a powerful initiation tool, just remember not to get too far ahead of the rest of your team.