Hw to prepare dt in final

I hv appeared in may 13 xams n got 42 in dt whereas my paper went quite wel.i didnt xpctd 42 atlst.waise to i hv applied for revaluatn.i tuk my classes from vg sir.plz suggst as how to prepar for dt cz jb itna acha papr jne pe b 42 diye to m rely afrd k kya likhu jisse numbr mle.i read al modules n supplmntry n rtp f institut bt stil 42.or kya pdhu.