This is the toughest requirement of being a consultant. This requirement is too often overlooked by people trying to get into consulting. You must be good at what you do. You can't be average. You must pay attention to details, have up-to-date skills, be persistent, determined, and obsessed with the quality of your work. You must insist on checking and double checking your work. If you don't have these qualities, then you probably won't last long. If your work isn't top notch, even if it's average or simply above average, your clients will begin to wonder why they are paying you so much to do the job. I've met consultants who could sell themselves to clients, but their work was shoddy. Their consulting careers never lasted very long.

It's best to also love what you do. Because you'll be doing it so much and there will be a lot of pressure on you to perform well, consider just how much you like doing it before "hanging your shingle."