Quinn top lane is a pretty strong pick if your team already have 2 tanks,it's a very high damage champion that can 1v1 most of top laners and punish them for farm.
On the lane phase, you're going to get as many kills you can, so, if you can't 1v1 your top laner or they're living under their tower, go roam around the map, especially if the enemy mid laner is low mobility (Like lux or tf for example).
And don't care about the farm that you're loosing in top, the kills and assists you'll get worth more, and help your team more.
And on the late game you're the assassin of your team, try to split push and try to always get the enemy by surprise, if the adc is isolated farming on bot, go kill him and get a free baron or ender dragon, on quinn you have a great pickoff potential, so you need to keep doing that, but with caution and having vision, of course.
On teamfights you always want to have their backline at your favour, so you can kill the carrys and win the fight for your team, if the enemy team have a janna or a nami for example, wait for them to waste all their peel to go all in, and if they don't waste it, don't go in.
If you're beeing focused to much, play like an ad carry, and peel for your adc, your Q and E can help then a lot.

Pros: Instead of a passive and tanky top laner, you'll have a pretty hard snowball laner, if you get fed during the early game you'll have a lot of impact on the late game, since you have great split pushing, it will cause a lot of problems to the enemy team since almost no one can 1v1 you.
Cons: Although she's a very good snowball assassin, she's very squishy, so if your team does not have at least 2 tanks (Jungle and Support), don't pick quinn! Tank meta is a real thing, they are pretty damn strong, so you need to have at least 2 on your team, and you can't pick quinn top to do the job of an adc, you need to play as an assassin. I don't like adc quinn because she's very low mobility (while in combat) and she literally has to jump on the face of someone (Her E), so this is a very punishable skill, and if the enemy team plays decently, will cause a lot of problems.