I started a company like this and ran it for 2y. I spent most of my time doing sales and client management, not building or designing. Read The E-Myth Revisited for an idea of the underlying issue of being a technician vs. business owner.

The market is highly competitive. Google "web design $YOURCITY" and you'll probably find dozens or hundreds of local companies offering the same services. The winners I've seen typically focus on a niche market, which helps them break out of geographic limitations and expand up-market to more lucrative projects.