For many of us who work with clients on various needs, scoping out a project correctly is key to maintaining a solid client relationship.  Clients get frustrated when taking on a new project is treated casually and they get hit with hidden costs.  It's important for both sides to know what is expected and what the estimated costs will be.  Here are some tips on how to make this smoother and maintain a solid client relationship.

1. Write everything down:  This can be challenging but it helps to have everything on paper.  Often there are lengthy discussions on a project and the client might change their mind several times. Document those discussions and exactly what is said.  Take notes on the dates of discussion and formulate the specs on paper first.
2. Don't start until it's clear:  I've often heard programmers say, "We'll figure that out later."  DON'T.  Figure it out now before you get started.  There will always be unknowns that creep up and alter the project. But make sure that it's clear when the project starts what the exact requirements are.  The more you have listed, the easier it will be to note the changes when they come along.
3. Sketch out the interface:  This has probably been the most meaningful step in scoping out a project.  Make sketches or design the interface in Photoshop or a similar app. This will of course depend on whether or not you know the client and are sure of the contract.  If not, then let the client know that you will do the work of putting together the scope and charge them for it. Don't be afraid of this.  It is MUCH better to lose a client than lose thousands of dollars because you started a project without a proper set of requirements.  Creating sketches and talking through them often leads to a much more complete project and reduces the amount of changes later.
4. Set reasonable targets:  As part of the scope, break up the project into smaller manageable chunks.  Present this to the client so they can feel comfortable that you have a plan (and you do) and that you have a clear vision for completing the project.

There are lots of ways to help make things smoother when you scope out a project, but the bottom line is that the more you put into the scope the less headaches and client frustration you will have later on when the project is being worked on.

Let us know of any stories or tips you have in making projects run smoother.