Some basics for heading into ranked eventually.
1.) Buy wards, no matter what role you play.
2.) If you are losing lane, don't play super aggressive unless you can secure the kill.
3.) Play champs you know how to in ranked, practice new champs in Normals.
4.) Mute people before ranting at them.
5.) Pick 2 main positions you are good at, and practice the others in case you need to play them. I'd suggest a carry role and support, since the reality is you will need to support some games.
6.) Pick 2-3 champs per position and spam them. Regardless of how boring it gets, you need to know you can get good solid play from your champ pool.
7.) Learn how to build per game. A lot of people make mistakes their builds every game, or just follow the suggested Riot builds. Do some homework on champs that you want to play and see what is viable and WHY, not just because it has a lot of stats. Even ADC's need to switch builds from time to time to mitigate the opponents carries or tanks.
8.) Proper runes are important depending on the champs/role you want to play.
9.) Watch videos of how professionals play. Personally, when I want to learn a new champ, I watch professionals play so that I can understand the proper order of skills to use or how to combo. Especially when it comes to high skill champs like LeBlanc, Zed, Lee Sin, Jayce, etc. or any champ that requires a lot of combo's to use properly.
10.) Understand what your job is in team fights, and learn how to focus on high priority targets. You don't want to focus the wrong roles in team fights, as I am sure you know that sometimes you get blown up in team fights due to good focus on a carry. I would suggest learning how to do this, as it will help your gameplay/experience in ranked as well.
11.) Learn what other champs can do, and what items they might play versus you. If you're an AP mid for instance and you're versus a Zed, you should probably know you should rush Zhonya's Hourglass for the +50 armor, and also the active erases his deathmark damage.
12.) Get used to using the actives on items. I know I struggled with this a lot when I started playing because I felt like so much was going on that I just needed to get my damage down range as fast a possible. You gotta remember to use items like Randiuns, Zhonya's, Ravenous Hydra; because sometimes it is the difference between a kill or a kill getting away.
That's all I have collected since I started playing, hope it helps and good luck!