The Winning Formula
There are three main areas that a freelancer needs to negotiate a good deal to ensure the best chances of satisfying the client and to be profitable:
Timeframe
Often, and especially those who don't understand the technicalities of the service you offer, clients have unrealistic expectations for how long it should take to deliver the solution they are hiring you to provide. Having a specific focus on the timeframe element will allow you to persuade the client to offer a delivery schedule that is more realistic to achieve. This is because it doesn't put you under pressure in a way that risks late delivery. It also avoids the project interfering with the time you have committed for other work you may be involved with.
Budget
The factor that is closely related to the timeframe and depth of the project, the project budget needs to reflect both what is delivered and when. A bad result in negotiating the project budget will not only restrict your profitability for the project, but...