Commerce

Along with Commerce graduation degree of B.Com or B.Com (Hons), you can do CA or CS. On completion of commerce graduation, you have options of M.Com or MBA or MCA. M.Com will focus on commerce, accounting, management and economics related subjects and prepares you for Finance and Accounting jobs in enterprises. MBA is a generic course on business management and administration and it focuses on functional areas of business such as accounting, finance, marketing, human resources, and operations. MBA provides wider options in different functions and various types of industries. Although you must do post graduate degree based on your interest area, I will recommend MBA with Finance specialisation for better career opportunities and growth. You can fo MCA if you want to have technical career in IT industry and have Maths as a subject in class 12.
In addition you can do PG diplomas in your subject of choice after B.Com including various certifications to enhance your career opportunities.

Accounts and mathematics: Start practicing questions on all the topics. Get all the previous year board papers, and solve them as if you are giving your final exam. Don't forget to learn the theory of accounts, it's equally important.
Business: Understand each topic and try relating it to the real business environment (or as if you are opening your own firm, what all points you would consider) and you will be able to tell the actual advantages and disadvantages on your own. Just a little bit understanding is required.
Economics: Understand the theory, practice the graphs, numerical.
English: You can't do much for the reading part. You can practice previous years writing section. For literature devote one full month to NCERT text books and read the chapters again, so that you can actually write the answers in NCERT language form (because checkers search for those main words of text book).