You just spawned
You are grabbing 3 mana potions and starter boots from the shop and you are running for the top.
The key part is to not press D for dance for it is indeed a trick :p.
Leash for your jungler if he asks for a leash but don't do a hard leash
(If you don't know why start with bots and work your way up).

Now, minions started to battle and the enemy top is here to farm, you have to remember your goal, your goal is to STAY TOP UNTILL YOU GET 6 STACKS.
You should already have your 6 stacks by minute 15 and it shouldn't be a problem but you never know.
How your team and the enemy team act is directly linked to how you act, by keeping the battleing minions near the center but closer to your tower you should be in able to avoid ganks easily and by harrasing the enemy champion with your 1. you should keep him busy so he doesn't wander off from the lane.
DONT ENGAGE THE ENEMY CHAMPION If you do so you might need to back which will slow down your leveling to level 6 and the cooldown of 5x 60sec.
However if the enemy champion attacks you backing to your tower might make you lose half of your hp
without damaging the enemy so shoot up your ignite and start autoattacking, if he starts to back away use your first and ult and he should be over.

If there are two enemies on top hold closer to your tower than you usually would and damage them with 1. untill your jungle is free to gank, than engage and when the jungler jumps in hit with your 1. and back down... Let him take the kills.... You will shine late game since you're a late game champion so it's better to let your jungler take the kills.

YOU GOT 6 STACKS! But what now?

Now just follow where the game takes you, stay at your lane and farm some more if you can or run amok and feast on the flesh of the poor champions who though you aren't op as ****....