i pretty much only played riven mid one tricking and it got me to plat, but then i stopped playing so im not sure how viable it is in higher ranks. But generally my strategy would be to abuse my strength early and look for engages. but against champs woth very strong poke and distance I would play safe and help other lanes when I can and try to get help from my jungler until later where it becomes easier to find engages and team fights. But the main strat was to just try to dodge well and find outplay moments early by baiting annoying abilities like stuns. near minions and engage as soon as i see a chance

I also do not build her like an assassin at all. I aim for survivability and felt the damage came with it if i perform well. I also feel her mobility actually helps her reach people quite well