Short answer: Work on weak sections with sectional tests, then attempt full papers to test stamina. Track speed and accuracy separately.
Sectional tests first
Take short sectional tests for quantitative aptitude, reasoning, English and general awareness. They show which section needs more time without the pressure of a full paper.
Full papers for stamina
Attempt a full paper once a week under timed conditions to learn how to manage the whole exam, including when to skip.
Track two numbers
Record accuracy and attempts per section. If accuracy is high but attempts are low, work on speed; if the reverse, slow down and read carefully.
Frequently asked questions
How many sectional tests should I take?
Take enough to cover each section regularly, and review each one before the next.
Is a used test book acceptable?
For reading solutions yes. For timed attempts a clean copy works better.