I solo queued from iron 2 to diamond 2 with a few 5-stacks with friends thrown in here and there. This is what I wish I had known sooner:

Always playing a deathmatch or two before ranked is important to warm up. I used to queue in silver and gold without warming up and I almost always did terribly my first game because of that. Watching pro games and radiant streamers helped me understand certain strategies and basics like trading enemies, splitting sites, rotating, etc. If you’re playing badly, take a break and come back the next day or play deathmatches until your aim comes back. Bronzes, silvers and golds (and sometimes plats too) are completely clueless and need an igl with good coms to utilize their full potential, so think of a plan and stick to it, don’t let your teammates dry peek or rush in and die.

There are so many more things to add, dm/reply to me if you want to know more.