Its good you are retaking the test, most people find it hard.
I got 306 in 2012, and left it, got deluged in work. I'm planning to retake soon though.
This time its a 330+ or die. Even if it costs me my left eye.
If you watched the Magoosh GRE intro videos, you'll learn that GRE tests your ability to take the GRE not your intelligence, it tests your academic skills overtime as well, like what you've learnt for the past 15 years, comprehension, communication, and basic math logic.
I wish you luck though, and myself too.