I have 400k into vayne i know what i am doing somewhat

The early game is difficult and all comes down to the matchup. Normally you want to play the lane safe and just wait to scale because with the crit build that is popular now you can one hit almost anything. Vayne's range really cucks her but her damage is really strong even in laning phase. If you can get your 3rd hit of you can do roughly 1/4 of the enemy ad's health and give you a bit of lane presence. Play around cooldowns and asking for jungle help is a good option because she is one of the most snowbally champions in the game.

try and farm to get ie and two zeal items and look to duel adc that think they can be safe pushing sidelanes alone. You can win a lot of 1v1 and even 2v1 if played correctly so be good and get kills.

Obviously as an adc you want to stay towards backline but due to your range it is difficult luckily you can melt tanks and outplay most assassins that dive on you. If the enemy team is cc heavy try and enter teamfights a little late and try and clean up the fight because if vayne isn't cc'd or exhausted you are free to go ham and carry.

You have reached full build and you are essentially god so just dont **** it up and do something stupid one hit everything get some life steal 1v5 make the front page of reddit