If you're a freelancer, then someone else is responsible for setting up priorities.
1. Before you get started, ask for a CLEAR set of PRIORITIZED tasks.
2. Provide estimates for how long it's going to finish each task.
3. Estimate risks, for each task, and add them to the tasks list. Make sure this is clearly communicated to the team you're working with.
4. Be clear about what "life", from your perspective may throw at you. This could mean a lot of things.
5. No surprises. Don't come in, the day before a task is due, asking for an extension. No one likes surprises, no matter the team size.
For freelancers, there's also the matter of where the next job is going to come from. So, you should schedule a daily task for yourself, called filling the pipeline. Make sure you also have a good contact list, of people who may run across jobs, or offer jobs. Be in contact with them on regular basis (email, calls, facebook, etc.). It helps to relieve anxiety.
What's your field?