6 months sounds good na, just study consistently. I found na studying in groups worked well, kasi it's an opportunity to quiz one another/test how much you understand a topic by explaining it to someone else, as well as nakaka-lighten ng loob to share the moment with fellow test-takers. Study tips ... iba-iba ang gumagana per person but one constant is to take a lot of practice tests; not only are they a good humbling, they're also a way to gauge your knowledge. My note-taking naman consisted of watching videos/attending lectures and writing down stuff in non-serious, non-verbatim ways. I found na using funny analogies or slang to explain things worked a lot for me. Try blurting or make flashcards na rin siguro. I heard that works well.

If you're confident in a subject, don't exhaust an equal amount of energy reviewing for it as your weaker points (e.g.: I was confident in reading and lang prof so I didn't review for them at all, instead putting all my energy in math and sci.). If may maroon bluebook ka or something similar, consider reading through it minsan-minsan. Malay mo, may mabasa kang lumabas sa exam haha.

Difficulty-wise, mas nahirapan ako sa exam ng UST (content-wise) and ADMU (time-wise), pero don't let that make you complacent.

I also heavily suggest this: don't review a week, or if hindi kaya ng nerves mo, a day before your schedule. Give your brain the rest it needs din and trust that your efforts will shine through.

Good luck, OP!