Don't be in a rush to 50, take time to enjoy the storylines and such.
i second this. the stories are the best part of the game. you don't want to miss out on them.
also, i suggest trying out all activities in the game at least once. i'm not usually into pvp, but i decided to give warzones a try. i actually like them a lot. flashpoints are always fun and a good way to get nice gear as you're leveling. if you ever need a break from questing, space missions are a good distraction. the daily quests for space missions give nice exp as well if you do the ones in your level range.