My tip is to drop 2 and take 2. It'll be a miracle if you can pass all 4 working part time.
F8 can go to opentuition.com and listen to their audio lectures. Helps a tremendous lot if you're diligent enough to go through them a few times.
F7: Practise and practice. Just no other way out.
F6: Highly recommend you get a lecturer. Yvonne Goh is good. A lot of things in the tax act won't make sense unless someone explains it to you. And you won't know what are the sections to focus on and memorise. There's virtually no way u can memorise everything.