Totally agree with David.

Many companies want to work with small teams and know that the portfolio / client work on the site, was created by the people who are going to work on their project - so if you're a small team, that means you.

Focus on quality work, not size of your team - cause honestly, in todays world ... it's less about full time staff, and more about access to high quality contractors and how you manage client expectations and projects.

The biggest piece of advice I'll throw out there is ... as an agency, your "product" is your methodology - so focus on that. Don't be everything to everyone, be focused on a core customer type and solution to a HUGE problem they have.

It will keep you sane as you grow.

Hope that helps.