Before you accept a proposal and start working with the designer or developer, you will need to ensure that the following is in place:

• Ensure there is clear understanding and acknowledgment of the full Scope of the project
• Schedule Breakdown for project (use the development brief document for this)
  
• Payment Terms - Normally done against broad milestones of the project, see the attached file for basic reference or you can get the developer to use the development brief document to insert project milestones and payment terms.
  
• Signed copy of business terms - You can work with your developer to come up with this document.

Sometimes scope can change as a project moves forward as you may decide to add another feature etc. Ensure that you discuss this possibility with your developer and how this process will be managed between you as there, quite rightly, will be an increased cost.