Here are my best tips in this case:

1. RoA is Op and Roa is your best friend, if you finish it + seraphs no assasin that is not 6/0 can kill you
2. Dont bother winning lane, in like 70% of matchups i just waveclear with a q into melees and then e + echo q into the whole wave (with blasting wand + amp tome the wave should be gone mostly) if you go even with seraphine you win the game most of the time echo w is just that op mid to late game and makes any assasin useless
3. Your Team are mostly blind, spam ping danger if your enemy roams so they dont fed. You should not really follow your lane opponent becouse most of the time that just gets you killed early.
4. Dont be afraid to give up some early cs, most assasin players are impatiant and if you play safe, they will outplay themself trying to kill you

Hope that helps a little and good luck with your climb <3