Preparing for entry tests is challenging especially for GIKI and NUST that have more conceptual papers. I appeared in the entry test for both the universities and passed with the faculty of my choice for both. A few lessons from my experience I would like to share here,
1) Follow your FSc books and try to grasp all concepts in the book. Going beyond the books might be useful but not that much.
2) Practice is key. Practice as many MCQs as you can. I found the website
http://pakprep.com very useful for practicing MCQs.
3) I did not find academies very helpful. Long lectures leave you braindead in the end. Better practice MCQs from good sources.
4) Do mock tests before the exam. Mock tests have same format as of the actual test and gives you the best practice. Again
http://pakprep.com has mock tests for both GIKI and NUST. I would strongly recommend doing those before the exams.
5) Relax before the exam, try your best and leave it to Allah for success.
Good luck for your test preparation.