Finding the lowest rates and best terms used to be a difficult task. Fortunately, with the proliferation of the Internet, finding the lowest rates is a lot easier today then it was in the past. Why? For example, EndThisDebt.com's refinance section is one example of how you can fill out one form and have your information sent to up to 4 mortgage companies instantaneously who will then compete for you business. These mortgage companies know they are competing for your business with other mortgage companies so they are more likely to start off giving you good rates and terms. But don't always assume that. Realize you have the power to negotiate because they want your business.
Mortgage companies have many different mortgage products they can offer you. For example, when you refinance you may want a fixed rate or an adjustable rate, you may want your repayment term to be 5 years, 15 years, or 30 years. Whatever the case, a mortgage broker's job is to provide you with a loan product that benefits you and yet represents a good investment for the lender.
Be aware of the current national mortgage rates (below) as you don't want to be demanding from the lender a rate that is not possible. However, don't be lazy. Speak to a few of the lenders that call you so you have a few quotes you can use as benchmarks or leverage when negotiating. Lenders can't just give you a quote unless they know your credit score and some other financial information so be prepared. Also be aware that you can negotiate closing costs as well which is why you want to get a few good faith estimates. Lastly, make sure you ask questions!