The best way to get solid feedback is start yelling at your teammate. They’ll retaliate and yell at you and likely tell you why you failed. Rinse and repeat.
That said, I would suggest finding someone around your skill level and just put in games. I would quite literally make a group and say “LF 2s/3s - learning XXXXcr” and then do lots and lots of games. While finding someone else to play with that is better can be tough, that can accelerate your learning, but just having someone to talk to about your losses is big. Always keep an open mind and leave everything on the table.
Outside of that, watch streams. Emulate their positioning, CC, CDs, etc. There are addons that help, but don’t get to many addons. Start with what you think you need, then go from there.