http://betterexplained.com/articles/how-to-develop-a-mindset...
In addition, I have found myself reviewing 'Discrete Mathematics w/ Applications' by Epp on numerous occasions;
My .02 - review logic / discrete math & move from there - The fundamentals of math logic and reasoning have been very important for me - I always felt this type of course should have been taught before a lot of the other subjects like Calc / Diff Equations etc.
Good learning!