2. Be Wary of Scope Creep
Scope creep is a constant for all IT projects especially and it usually refers to the way a project's requirements typically change during different stages of the project. In particular, scope creep tends to happen during update meetings. As clients are informed on how work is progressing, they begin to see things a bit differently. Perhaps they want a landing page to look just a bit different, or they dream up a new feature that the app you're developing must absolutely have.
These changes, big and small, can really impact whether or not you can stay within the bounds of your original, project estimate. Worse, as clients request these changes, they may not realize the impact they are having on your budget. The end result of this is that clients often become frustrated with you for failing to stay within the budget estimate.
To create a project scope document that works for you, look for example documents and templates that are relevant to your industry. Remember that you are better off erring on the side of being too detailed rather than less so.
If your initial project document isn't clear, and very explicitly detailed, that can lead to problems. Therefore be sure to detail what will be included within the scope of the project. More importantly, detail what will not be. This will help to keep discipline within the process.
All this will serve as a project baseline. This way, when the client makes changes, any resulting changes can be properly budgeted and attributed to them. Also, don't forget incidental items like travel expenses, mileage, etc. These can add up and included as a part of a revised budget.
Besides, to make sure the project won't deviate too much from your client's expectations in terms of both features and budget, see that there is a proper change order procedure in place. This will not only protect your company, but it will also set pre-conditions for your clients. This is one of the biggest benefits that comes from contracting out work to developers. Companies with in-house IT departments are virtually unable to instill change order procedures, leaving themselves exposed to extra expenses and exceeded deadlines for lack of clear budgetary control.