Treat ranked the same way you treat normals... because it's the same thing. There's hidden MMR as well here, meaning that if you land in bronze 5 due to terrible luck, as long as your mmr is above that you'll be gaining a lot of LP each win/losing very little LP.
First ten matches, absolutely dodge if you see an incoming doom in champ select (trolls, ragers, etc). Dodges don't count as placement games and you don't lose LP either.
In ranked, there are two types of people - those who try hard (generally like 60%) and those who first time champions and generally treat it like normals (like 40%). Over the first few trades decide whether the other guy is better or worse than you and play accordingly (aka harass the weaker guy, be cautious against a better one).
That's about all that comes to mind. Just don't treat ranked like something special - it'll only make you feel nervous. In terms of seriousness, it's more than enough to take good matchups with champs that you mostly play. I don't suggest first timing champs in ranked though, partially because you make yourself feel nervous and partially, well, because you can show like only 50% of skill that you have after spending 1 match of normals/bots when training.
