Sona is my main support, and pretty easy to pick up. Basically press any button to help your team. Her ult takes time to become good with though.
Taric is probably the easiest support, next to soraka. Neither one is reliant on skill shots to succeed.
Early on id say go for taric/raka, but save up ip for when you discover your support playstyle. Some people adore leona, others nunu, but it comes with time.
The thing I hate about bottom lane solo q is differing playstyles. You have to match your adcs level of aggresion. As long as you ward, keep some bush/lane presence, and talk to your adc about style youll do fine.