i m BE final yr avrage studnt not sure for campus..sugges me how to prpare for aptitude and entrance exams (-skm-)

actully most of the tyms i used to find myself in confused situation means things i know but can't visualise it on the tym,which makes me bit looser,let me know how can i change dis into my strength. dats why i call myself an avrage student. pease advise me...i need dat!!!