Tip #1: Look for a Strong Portfolio
The sites that a web developer has worked on are typically strong indications of the type of work that you can expect from them for your own website. When reviewing a developer's portfolio, keep an eye out for aspects that you want incorporating into your own site. If you are looking for a bleeding edge design, then look for those types of designs in their portfolio. If on the other hand, you are looking for complex programming, make sure you tell the developer that you would like examples of those types of sites.
Tip #2: Understand Who Will Host Your Web Site
How a web development company hosts the websites that they create is an important but often overlooked aspect of choosing a web developer. Many web development firms simply act as a reseller for a company that performs the hosting. The danger with this is that if you experience problems with your website or email it sometimes isn't clear who is responsible for fixing the issue. This can result in finger pointing between the web developer and the company involved in hosting the site when a problem occurs. This can be especially problematic with complex websites that perform e-commerce or other custom functionality. Make sure that you understand who is responsible for assisting you with any hosting or email issues that you have before signing on with a web developer.
Tip #3: Look for Specialization
Many web developers claim that they can do it all. The truth is that most web developers are primarily either graphic designers or programmers. The fields of graphic design and programming are fairly specialized and it is uncommon to find people who are able to do both good. When looking for a web developer, we recommend asking the professionals to designate who will be designing your website and who will be doing any custom programming. If it is the same person doing both pieces, we advise paying even closer attention to their portfolio.