Mocks - they are important. You can learn and cram all the concepts and facts. You may do pyp well, but don't underestimate the value of mocks. Sectional mocks can be skipped, but do attempt ~ 10 full length mocks. I remember giving one ForumIAS Simulator test, found it so absurd and random, thought UPSC don't ask these questions neither UPSC is such random and the rest is history. The one thing I have learnt is that be ready to test yourself in every situation, UPSC can throw any bomb be ready to face any situation.
Give some full length mocks. They'll help to recognize how much questions to attempt, how to approach the paper and so on. PYP are imp, but they only tell what topics are important, which type of questions come and what type doesn't.
And lastly train yourself to not panic. If I have not panicked in prelims this year, may be I had stopped myself from over-attempting.
