repetition is the key...
work on your weak areas but still maintain a solid confidence level on your stronger areas...
grind through more practice problem... remember to think of this as a game (and not a test) and maybe that'll help and motivate you through your studies...
other than that, we really don't know what to say unless you give us more specifics about areas of improvement. DS? learn the tricks. SC? memorize idioms and structures... RC? read more boring materials (for me, law and politics are super boring for me, so i try to read passages on these topics) etc...