How to start

better to get at least one reference book  for each subject. books of good author will make  you clear concepts. then you can go for study material.  

Can you suggest me best reference book publisher.......??

Ok right now what i am following are tax girish ahuja accounts pc tulsian law munish bhandari audit surbhi bansal and padhuka Itsm institute material moreover i would say for audit use only surbhi bansal book if have guidance. If you are totally relying on yourself go for padhuka for detailed study and surbhi bansal for revision. These are my picks i would suggest you to go to book store and check out yourself. As i am taking coaching for three subjects I feel these are good enough for me.