The first thing should be to prepare a time table as per the availability of time with you. The time-table should not be just to enhance the beauty of your study table. You should follow it strictly and devote decided time to each subject.
If you still find it difficult to manage the study time on your own, you should take admission in a reputed IAS coaching center. The benefit of joining a coaching center is that you will have to study for specific hours every day. Gradually, you will develop habit of regular studies for 8-10 hours. Further, teachers at the coaching center also tell you different tricks to make most out of every minute to cover complete syllabus for IAS exam