Just check here https://gateoverflow.in/activity , see the questions asked here, also click unanswered tab and questions tab and solve all type of questions you can able to solve , this way you efficiently use GO.
For topic-wise tests click these links :
https://gateoverflow.in/exams/tests-by-mentors?type=3
For full tests :
https://gateoverflow.in/exams/tests-by-mentors?type=1
Answers are all discussed in those tests , when you generate the pdf after each test, click the discussion , you will get the exact discussion thread for that particular question.
FOLLOWING ARE THE TEST LINKS:
1)https://gateoverflow.in/exams/tests-by-mentors?type=3
2)https://gateoverflow.in/exams/gateoverflow?type=3
and you can discuss your doubts here
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