If you plan on moving out of your existing home within the next few years, it may not be beneficial for you to refinance. Make sure you let your mortgage specialist know your future plans.
Stick with a simple loan. It is easier to understand and less likely to get you into trouble. Adjustable-rate mortgages may seem like a way to get a bigger house now or to keep more money now, but when the rates adjust you can get into trouble. Avoid anything with a balloon payment. Just choose a simple 30-year mortgage you can easily afford.
Be Realistic. Lenders have tightened up loan requirements, so you'll need a good credit score and at least some equity in your home to refinance. To figure out how much equity you have, subtract the total amount that you owe on all of your existing mortgages from how much you think your home is worth. If your credit is severely impaired or you owe more than the value of your home, you probably won't be able to refinance right now.
These days most people request a Good Faith Estimate (GFE), but have no clue what to look for on the GFE. Make sure you request a GFE that has ALL fees estimated and disclosed. This includes: origination points, processing, lender, appraisal, title, escrow... ALL FEES... especially the Yield Spread Premium or YSP.