Every student has its own unique way of studying so after your boards also you have enough time to be well prepared for the exam, but I would suggest you that from now you try to give some time for CLAT topics whenever you get tired to study with your 12th syllabus, at least go through with the previous year papers of CLAT to know the level of the questions. Here are  some of the tips which are basic & helpful for you:
1. Know the CLAT paper pattern, marking scheme, changes in previous year, latest trends and participating colleges.
2. It is not the quantity of books but the quality of books which matters. So make sure you have a selective yet good books with you.
3. Start with previous year CLAT question papers and previous year papers.
4. Be updated with General awareness, current affairs updates and even legal updates.
5. Work on your vocabulary. Read newspapers and relevant novels. This will also help you in increasing your speed.
6. Areas of Law to be understood in basic form includes: Law of Torts, Law of Contract, Constitutional Law, Criminal Law and some understanding of Family law.
7. Also do not forget the main part which is attempting online and offline mocks. There are sectional and full length mocks available as well. Material you can refer to are: -Previous year question papers -Norman Lewis- Word Power Made easy -Verbal and Non Verbal Reasoning- By RS Agarwal -Universal guide to LLB Exam -Pearson GK Module -Monthly magazines on GK, Current Affair, Books and Novel.

Good Luck!