I think that the teacher's experience in teaching and marking STPM papers is essential. STPM isn't an easy exam, it's actually mind numbling ie: Maths 1 2005, after the exam I was mentally drained. You can never expect what question that comes out. The only way to prepare is to do enough on un-routine questions that challenges you to think out of the box.

For those who took the exam last year should remember the Maths 1 hexagon vector question. Passing shouldn't be a problem, but like what my tuition teacher said, they'll always get you at one or two question that'll cost you the A.

I had a crappy math teacher that couldn't teach worth shit, we were actually teaching her the basic, tuition was the only solution for us.

If you're only studying using the text book alone, think again. The best way is to do past year question after you've studied a certain chapter, but sometimes questions from the exam incorporates more than one topic in a single question. Also, a most common misconception is that you only do exam questions when exams are nearby. Have your past year exam papers and try giving them a go a topics you've already covered.

Having said this, I never regreted doing form 6, never.

Tip: Don't believe 100% in spotting questions, finish the syllabus ASAP and do a review on what you've studied.
Tip2: Short notes, life savers. 'Nuff said.

As long as you put in effort it wouldn't be. Not the kind of effort where you start studying seriously only 1/2 months away.

Just start early and you should be fine. Always try to do a topic review after you've finished certain chapters/topics,make your own short notes, attempt pass year questions and you should be fine. Scoring an A would require extra effort.