If you are starting now, finish your first reading by next months. Remaining three months, your properly planned revisions should be done.For first reading-
1. Limit your resources- You can refer booklist available on UPSC Panda
, clearIAS, ClassicIASAcademy etc. Focus on only these books.
2. Make a Time Table and follow it strictly.
3. Thorough study of NCERTs- Remember, NCERTs is the base. You have to revise it again and again.
4. Keep an eye on Previous Years Papers – Along with reading, Previous Year Questions can guide you about the weightage of that particular topic in exam. Cost-Benefit analysis needs to be done.
5. Current Affairs should not be ignored. You can refer any monthly magazine for Current Affairs. Try to cover one year Current Affairs.For Revisions-
1. Plan multiple revisions.
2. Revisions have to be fast. Like 25 days for first revision, 20 days for second, 15 days for third and likewise. It will help in keeping the momentum.
3. Test Papers must be solved. Evaluate yourself through Test Papers and work on your weaker areas.
4. If required, increase your study time.
5. Remember one thing, these three months rigorous preparation can avoid preparation for next 2 years. Do put your sweat and blood in the preparation.
6. Last but not the least; keep reminding you about your goal. It will keep you moving even in the time when you feel demotivated.
Hope it's helpful.
All the best.