Who can you support other than Taric, be honest it doesnt matter how few you can i just need to know. Support (although not always seen) IS the most important position during the laning phase. You feed and protect the AD carry. His success reflects on your success. Taric (Although a very strong character) doesnt synergize with every character. This helps alot whenever you need to pick the right support. Now you dont always have to follow the rule, if you are uncomfortable with playing that character dont do it. I urge you to play some draft games to get in the swing of ranked games. Also look up guides and read it all, usually people on read the items but i find that the most important part of good guides are HOW to play the character and how to use their abilites to the upmost effect. Play with Deks a couple of games to get your limites and boundries. As always i wish you luck as your app continues
TL:DR Try to learn more champs,look up guides, synergies and counters, play with deks, Teemo is a bitch