How do you eat an elephant? Piece by piece. it sounds stupid, but start at the beginning, and pace yourself. Chapter by chapter, you'll get through it.

I'm really poor at math, so I've learned to work slowly and check if I really understand something before I go to the next chapter. Most maths is based on previous work / understanding. So, when I rush or try to skip pieces, I misunderstand the next part, making my rushing completely useless.