2.  Settle for deletion, or at least zero out all unpaid collection accounts less than 24 months old    

    You need to pick your battles as to which accounts you focus on during the credit crunch to assure your credit score increases enough to get your loan approved.
    When payment is made on a collection account that is less than 24 months old, the score will either stay about the same or increase a few points. Settling in exchange for deletion is ideal, but not always possible. Given the fact that the collection account will keep selling to other collection agencies in the future, it is best to deal with it while it is still young.
    Once an account goes beyond 24 months, you need to be careful when settling, because the account may erroneously have the date of last activity updated to the current date and bring the score down as a result.

    Within the delinquent accounts on your credit report, there is a column called "past due." Credit-scoring software penalizes clients for keeping accounts past due, so past dues destroy a credit score.
    If you see an amount in this column, pay the creditor the past due amount reported, unless that amount belongs to an account that is charged off or in collection. If that is the case, use the advice in number one above to determine the best action.

4. Get rid of your late payments

    Contact all creditors that report late payments on your credit and request a good-faith adjustment that removes the late payments reported on his account.
    You should be persistent if they refuse to remove the late payments at first. Remind the creditors that you have been a good customer and would deeply appreciate their help.

5. Ask for a credit limit increase on your credit cards and either pay off, if possible, or, at a minimum, evenly distribute the balances that you are carrying on your revolving debt    

    Credit-scoring software likes to see borrowers carry credit card balances as close to zero as possible and also see that they have been trusted with a lot of credit, which is why increasing their limits is good.
    If you can't afford to pay down your credit card balances, evenly distribute your credit card balances among all of your credit cards, rather than carry a large balance on one credit card, to maximize your score.

6. Remember "Do not close your credit cards"

    Closing a credit card can hurt your credit score, since doing so affects your debt-to-available-credit ratio. For example, if you owe a total credit card debt of $10,000 and your total credit available is $20,000, you are using 50 percent of your total credit.
    If you close a credit card with a $5,000 credit limit, you will reduce your credit available to $15,000 and change your ratio to using 66 percent of your available credit.

7. Keep old credit cards active

    Fifteen percent of a credit score is determined by the age of the credit file. Fair Isaac Corporation's credit-scoring software assumes people who have had credit for a longer time are at less risk of defaulting on payments. Therefore, even if old credit cards have horrible interest rates, closing those cards will decrease the average length of time you have had credit.
    You should use old cards at least once every six months, to avoid the account rating changing to "inactive." Keeping old cards active can be as simple as pumping gas or purchasing groceries every few months, then paying the balance down.
    An inactive account is given less weight by Fair Isaac Corporation's credit-scoring software, so you wont get the benefit of the positive payment history and low balance that card may have as much as if the account were active.

8. Pay down negative amortization mortgage balances below the original amount borrowed to increase the score

    Most people don't realize that owing more than the original amount borrowed on a loan is a negative event to the credit score. If possible, pay down the balance on any and all negative amortization loans that you owe more than the original loan amount. This includes mortgages and student loans. Once you bring the balances below the original amounts borrowed, a credit score increase of five to 10 points is very common.
    Don't confuse this advice with labeling a negative amortization loan as being bad. They can be a great financial tool, when used appropriately, and make otherwise unaffordable payments affordable. They can be great, as long as you are not in the middle of a refinance. But, if they are, paying these balances below the original amount owed can maximize your credit score.