I don't have time to go through all the posts but this is what I have to say, start early, be consistent, and most important UNDERSTAND what you are learning, don't learn blindly.

Derive your own concepts which will help you to understand concepts in physics, add maths, chemistry and biology. Many people say Pelangi is useless, too thick, information overload but I beg to differ. They go into great length in explaining every reasons, like why size of elements increase across the periodic table, etc.