Get the book "Thinking Mathematically" (http://www.amazon.com/Thinking-Mathematically-J-Mason/dp/0201102382 http://www.amazon.com/Thinking-Mathematically-J-Mas

Get the book "Thinking Mathematically" (http://www.amazon.com/Thinking-Mathematically-J-Mason/dp/0201102382 http://www.amazon.com/Thinking-Mathematically-J-Mason/dp/020... non affiliate link) which exposes the process of how mathematicians think, using simple problems. You can then adapt the process to your preferred level of problems. Also learn proof technique (Velleman's How to Prove it" is a good book for this) and doesn't make any assumptions of mathematical knowledge.