No matter how you determine your fees initially, you will need to consider your experience, your client's budget and the current market value of your service. Once you and your client have come to an agreement on how much to charge and the details of your assignment, make sure you follow up with a written contract or letter of agreement signed by both parties outlining exactly what is to be done. Experienced freelancers say this is the best way to avoid misunderstandings down the line. If there is any question about how long a job should take, be sure the agreement indicates that you are estimating the time and that your project fee is based on a certain number of hours. If you quote a flat fee, you should stipulate in the agreement that a higher rate might be charged for overtime hours or late changes in the project.
Communication is important in dealing with clients.
Make sure they know right away if you find the project is more complex and will take more time than you anticipated. Leave yourself open to renegotiation and, again, be sure to put any renegotiated fees in writing. On big jobs, some freelancers ask for partial payment at different stages of the project. Some figure this into their flat fees, but if you require reimbursement for extensive photocopying, postage, gas mileage, etc., it's best to make sure your client knows upfront and that you get it in writing that these expenses will be paid. We've noticed a few trends worth mentioning, too.