hey nitish!

This is a very opinionated question and is open for debate. Well there is no easy way to crack an examination, all you have to do is to study hard and focus on smart work not hard work.

About political science , Yes , it is no doubt a very good subject for UPSC only if you have interest in this subject . Don't look for easy subjects, do some self - introspection and find out the subject of your own choice . that will be interesting to read and easy to understand.

Hope it helps!!