If you're just getting started and don't have a huge set of clients to keep you going, you need to build trust and reputation. The best way to do that is to deliver more than you promised. Throw in something extra, or do a little more than expected. In the long-run, this will earn you some extra thumbs ups, some good word of mouth, and definitely some returning customers. As a freelancer, those returning customers are invaluable. Otherwise, you're spending all your time marketing your services, and never actually delivering services which is what pays.
The 2 best advice i can offer for freelancers is this: - If something doesn't work - don't be disheartened! Change your approach, seek advice from experienced members & try & try again! - Maintain a good relationship with your customer base. Don't take things personally & remain professional at all times! - (A 3rd point - (because i think it's important...) never be afraid to ask for help! Jake