What they do all day? Companies from startups to the Fortune 500 hire information technology consultants to figure out the fastest, cheapest and most reliable ways to make their computer systems run better. They assess a firm's tech needs, create a plan, see it through and follow up to make sure it's running well.

How to get the job? The single-most important piece of advice for IT consultants is this: Specialize. Information technology covers a wide swath of categories -- hardware, software, networks, Web design, communications, to name just a few. A successful consultant will find a niche and let experience do the talking.

What makes it great? Even big businesses know that high-level tech issues can be a Pandora's box of trouble. A sharp IT consultant with the right specialty will command a premium rate and solve a company's problems -- ensuring future work down the road.

What's the catch? Specialization can feel limiting, but consistency pays off. Spreading oneself too thin can ruin a good reference, and references are the lifeblood of consultants. --T.Z.