GMATPrep 370....45 days to reach b/w 500 and 600--HELP!

Tips for data sufficiency:

Read the question.

Read statement 1. Assume it is true. Evaluate whether the information provided in statement 1 is enough to answer the question. You do not actually have to solve the problem, but you must determine if the information given is sufficient to solve the problem.
If you find that the information in statement 1 is sufficient, you automatically know that the answer will be either A (statement 1 alone is sufficient, but statement 2 alone is not sufficient) or D (each statement alone is sufficient to answer the question).
If you find that the information in statement 1 is not sufficient, you automatically know that the answer will be either B (statement 2 alone is sufficient, but statement 1 alone is not sufficient), C (both statements 1 and 2 together are sufficient to answer the question, but neither statement alone is sufficient), or E (statements 1 and 2 are not sufficient to answer the question asked and additional data is needed to answer the question).

Now, completely ignore statement 1 and only focus on statement 2. Read statement 2. Assume it is true. Note that the GMAT wants you to assume both statements 1 and 2 are true, and thus cannot contradict one another. Evaluate whether the information given in statement 2 is enough to answer the question. (Keep in mind, that once you have reviewed statement 1, you can narrow your choices to know the answer will be either A or D, or that the answer will be either B, C, or E - you can always narrow down to these two groups)

If after reviewing statement 1, you decided the answer was either A or D, read statement 2 and determine whether it is sufficient to answer the question alone. If statement 2 alone is sufficient, you know your answer is D (because you already determined that statement 1 alone is sufficient).
If after reviewing statement 2, you decided the answer was between B, C, or E, read statement 2 and determine whether it is sufficient alone. If so, the answer is B (since you already determined statement 1 alone is not sufficient). If it is not sufficient alone, but you can solve the problem with both statements 1 and 2 together, the answer is C. If neither statement alone is sufficient, the answer is E.

Hope this helps! If it confused you even more, let me know and I'll try to explain further.