Tutor/Coach?

Sorry for the long post. :D

I'm currently looking for someone to join a few games and give me some tips on mechanics and builds(I only really play once a week on Tuesdays). I haven't entirely decided on a main champion, so I just pick whatever I feel like playing at the time. I'm a mid lane main with support off main. I do decent in some games, and absolute trash in others due to pairings and my bad decision making. I suppose I'm looking for safe and/or mobile mid laners with decent burst damage.

Here's a list of who I play: Top Lane:

Jungle:

Mid Lane:

ADC:

Support:

I have more champions than the ones shown, however, these are the ones I usually pick the most. The rest, I still need practice with, same for ADC, Top Lane, and going Jungle. I feel like I play aggressive when I'm mid lane, and play kind of passively when I go support(unless Blitzcrank). My item builds have little variations, so I'm usually building the same stuff. I've gotten better about it as of late, however, it's still kind of difficult to tell what I should do based on looking at their items. If they're building Offensively, I will either go defensive or build offensive if I'm already ahead(which doesn't happen all that much). I may be stuck in an ELO worse than what I'm meant to be in, so that could be another issue. I'm not entirely sure. ._. I haven't started playing Ranked yet, simply because I don't believe I'm good enough to do so, and I don't have the necessary runes for a lot of my champions.

I guess I'm just looking for some tips & tricks, some guides, and recommendations for some champions.