Speed!!!

Hey frnds.... I m writng ma exams dis may...nd need sum advise frm u people!! My speed in writng practical papers is very slow...though i solve problems while practisng by hands bt stil unable to increase ma speed...i had suffrd a lot bcz of dis as i was nly able to attmpt 60-70% of paper as a result of which i m unabl to score wel though i knw d answers!! Plz help me asap...:(