If you're a mortgage newbie or you're refinancing, you may want tips on what to do--or not do--in taking out a home loan. Even if you've borrowed before, the mortgage landscape has changed so much since the housing crash that you may be unpleasantly surprised by new rules and practices that didn't exist before.

DON'T...

Pass Out Private Information

To give you a meaningful mortgage quote, mortgage lenders need your credit scores, loan amount, down payment (or home equity), property type (single residence, condo, duplex, etc.), and property use (primary residence, second home, rental).

Don't give out Social Security numbers or other private information until you choose your mortgage lender and apply for your home loan.

Back Down

Don't sign anything unless you understand it and are comfortable with the terms. The real estate agent, loan officer, or property seller won't be making your mortgage payments or living in your home, so don't allow them to pressure you into anything you don't want one hundred percent.

Change Things Up

Don't switch jobs until escrow closes if you can help it. Don't decide to sell your car to get the down payment if your application says the funds will be coming from an investment account, unless you wantto toss your file back into underwriting and delay your closing.

Don't finance large purchases or apply for new credit, and don't miss any payments. New quality assurance procedures require mortgage lenders to pull your credit again right before closing, and changes for the worse can cost you additional fees or even endanger your loan approval.

DO...

Check Your Credit

Take a look at Fannie Mae's Loan-Level Pricing Adjustment matrix to see how credit scores affect today's mortgage rates. A borrower with a 679 FICO score can pay a full point more than someone with a 680 score. Get your credit report for free from www.annualcreditreport.com, pay the extra charge to get your credit scores, then see if any errors need correcting--well before you apply for a mortgage. You may be able to save thousands just by raising your FICO a few measly points!

Get Preapproved for a Purchase or Refinance Mortgage

Being preapproved tells sellers that you're serious and able to close the deal, which strengthens your bargaining position. Being preapproved for a refinance helps you close quickly when rates drop into your target zone and you want to lock in.

Read Your Mortgage Disclosures

Your Good Faith Estimate (GFE) discloses the most important features of your new home loan or refinance mortgage--the interest rate, potential for rate adjustments, any prepayment penalties--and what the loan costs. Your Truth-in-Lending (TIL) form contains the annual percentage rate (APR) and the total interest paid over the life of the loan.

After you get the forms, read them carefully. All the disclosures in the world can't help you get the best home loan if you don't take the time to read them and understand what you're getting into.

Shop for Your New Home Loan

Lenders' mortgage rates on a 30-year fixed loan can vary by nearly half a point, so of course you should compare them. You can reach several lenders in one shot by completing and submitting a form online. Request Good Faith Estimates, which are actual interest rate and fee commitments from lenders that they must honor. Make sure the terms apply to someone with your credit score, down payment (or equity) amount, and property type and use.

Mortgage shopping today is different than it was even a few years ago, but attending to these do's and don'ts can make it a productive and profitable experience.