Hi Mgm, the algorithms for FICO scoring are not static and move to rules that change as your credit profile changes. Fair Issac, the creators of the "predictive analytics" credit scoring model do not want anyone to know how it "ticks" so it is not possible to "engineer" one's score.
There are some basic percentage breakdowns that make up a score, which you can find here http://docs.Steven-Anthony.com/SAR-YourCredit.pdf
but again, these do change as one's credit profile changes. Read the "Top 10 Do's & Don'ts" contained in the link above.
There's a "Rapid Rescore" capability (ask your mortgage broker) that allows you to update all three credit agencies ASAP but this will cost you upwards of $150+, depending on how many accounts you are updating. You can then immediately pull your credit again. Other than this, most accounts are updated the beginning of each month.
I have no clue what your score is right now, but if you have a mid-score of 620 right now you can buy using an FHA loan, which has some interesting benefits:
1) 3.5% minimum Downpayment.
2) Up to a 6% Seller Credit allowed for buyer's closing costs and Seller concessions (non-FHA max is 3%).
3) FHA requires that identified safety/health issues be corrected.
4) FHA allows up to $8,000 in financed energy efficient upgrades without negatively affecting borrower's debt-to-income ratio.
5) Cash reserves not required.
6) Upfront Mortgage Insurance may be financed.
7) Non-occupying co-borrowers are allowed.
8) High and flexible qualifying ratios.
9) FHA loans are assumable.
10) No pre-payment penalties.
11) Will consider "compensating factors" in determining whether a loan should be granted.
Perhaps the only negative: While FHA only requires a 3.5% down payment this means you will be financing 96.5% of the sales price and you will have to pay Mortgage Insurance for a MINIMUM of 5 years, or until you have paid your original LOAN AMOUNT down to 78% (not that the loan amount is 80% of current market value, which is typical for non-FHA MI removal). This "78% or 5-year Rule" before Mortgage insurance can be terminated is covered here: http://www.hud.gov/offices/adm/hudclips/letters/mortgagee/fi