When in the construction business, estimating a project is a large part of the job. In the beginning, you will probably see inaccuracies, due to lack of experience. It's possible you may overbid or underbid a project, not calculate wages correctly, and run into other unforeseen issues. To help overcome some of these difficulties, try downloading a variety of estimate sheet samples like these:
. http://www.docstoc.com/search/Project-estimate-sheet/. Finding examples that are similar to your line of work may help stop problems before they occur.