well improving writing skills is not a joke ....bt its also not dat tough ....all u need 2 do is regular practice....bt i guess dis is not d tme 4 doing so ..........as u mst b wanting a temporary solution 4 jst getting good marks in exams ...so u better jst prepare 4 some basic topics ....n topics given in sample papers n previous year board question papers....well u r frm 12th right........r u having  MCB in 12th like d 1 v r having in 10th ...........if yes ............den jst prepare 4 d topics given in it .......dat wud b enough ......so all d bst 2 u ............i hope u gt good marks .....................