Sell, yes. And if you build excellent client relationships (LOTS of communication and honesty is good) then your clients should keep coming back to you for ongoing work.

Additionally you want your clients to be your biggest cheerleaders and talk you up and recommend you to their associates and friends for work.

You can even offer a referral fee, I've done this, but generally if people like you, they're happy to make referrals without even being asked.