Noob alert - Can anyone give me feedback?

TL;DR - I'm a giant noob and would appreciate advice/insight. :3 Even tips on how I'm reviewing the match would be awesome. This is my first time seriously "analyzing" my game and I want to do it right.

Hi, I've always played this game casually (and love it!) and felt like ranking for the first time soon, so any advice would be really nice. I just had a game where my team lead most of it, but we threw and lost. We were constantly:

1. getting caught out in areas without vision
2. engaging/disengaging team fights constantly instead of poking (i.e. starting fights without ping/warning in THEIR jungle while we're still far behind, moving across ours)
3. not focusing enough on objectives
4. overextending (kinda like 1?)

I'm guilty of overextending/not clearing wards, not buying pinks, forgetting to buy/use oracles (urg, I do this every time) and some bad placement in team fights. I'm working on all of those but let me know if there's anything else you can pick on me for, or if my observations are wrong/too vague. Map awareness got way better.

As for team fights, they were constantly going on because of someone getting caught out or because we were greedy for kills (not so much towers or jungle monsters). I didn't like the majority of team fights because I wanted to get towers/win, not always start fights. (Poking first would've been nice, but they'd go totally ham which surprisingly worked a lot.) In the end, we had one big team fight that threw the game. How do I convince my team to stop constantly going in (at least, without some poke or element of surprise)? It felt more like a face off than a strategy game. But I suppose it's better to go all in than go 4v5...

I'm sorry if this isn't the place to put this, if it's allowed at all. (I read the guidelines and didn't see anything against it.) Let me know and I can take it down without being super reported.

Thanks for making League, it's the first game I've ever seriously played other than Tetris. ^_^