I. Remember to try visual aids!! Look back to your notes, and/or check out the visual aid section in any business textbook. Creating visual aids may help you to create a more stylistic document. In the case of the evaluation section, you may find that a chart supplements you prose effectively!!!
II. Evaluation section- use this formula: X is or is not a good Y
In the case of the feasibility report, the X is going to be the specific "potential" solution and the Y represents the "practical" or "good" solution. You purpose, then, is to define the "good" solution by the criteria and then to test each possible solution by determining if "X" meets all the definitions of "Y". If it does, then you've got a GOOD or FEASIBLE solution. Please note that the criteria must be relevant to the business or organization.
III. Parameters to the criteria
Sometimes you can make a persuasive argument by clearly defining the "parameters" of your criteria. For example, cost-effectiveness is always relevant to companies, but where are the lines drawn between being "cost-effective", or not "cost-effective"? Map out the boundaries for your criteria, and your argument will be much more precise!
IV. Evaluations (in a quantified manner)
Remember when I spoke about using numbers as a persuasive force (compared to words?)? Well, use this to your advantage. If you can come up with a numerical system of rankings, interspersed with your evaluation, you could include a "mathematical" argument!