Why is a premium domain name so important? For one thing, a premium domain name can help you get the traffic to your website. If you don't get traffic, you might as well not even have a website. There's no doubt about it, if you want to make money, you need traffic.
A premium domain name can help you to get traffic in a couple of ways. First of all, if your domain name is catchy and easy to remember, that will help people to find your website and to return for future visits. It's also a good idea if your domain name gives some indication of the type of business you have. For example, if you want to have a website that helps people find realestate, it would be a good idea to have a domain name that contained some or all of those words. You might do good with "beachrealestate.com" or something similar.
Again, it's really important to embed keywords about your business into your domain name for good search engine ranking. You'll find that most of the high traffic websites with short, unrelated domain names get their huge amount of traffic thru paid promotional campaigns. They use radio & TV ads, high volume email advertising and other such methods that might be too expensive for a small business just getting started.
A good way to find your premium domain name is to develop a list of keywords that are strongly associated with your business. Write down as many keywords as you can think of, as long as they're on your subject. Once you have your list, you can use one of the several free online tools to help select just the right domain name for your new website.