Hey.

For GK and current affairs, first of all develop a habit to read newspapers daily. The Hindu is the newspaper preferred by various law Aspirants. 

English - For Vocabulary you can refer the Word Power Made Easy. You will come across various words while reading the newspaper too, prepare a list, go through them regularly and try to use them in sentences. You should read the Editorial section of the Hindu for your Reading as well as Vocabulary section.

For grammar you can use the Wren & Martin.

Mathematics - For Quantitative aptitude by RS Aggarwal. Other than that previous year question papers and Arihant/ Universal guide migh help too.

Legal Aptitude - Universal’s guide to LLB is very helpful. And for Logical Reasoning - RS Aggarwal or Universal's guide.

Make sure that you go through the past year question papers and practice them along with sample papers.

Best of luck!