How you phrase the requirements depends on what you want the end result to be. Sorry to start this off with a wishy-washy statement, but when dealing with contractors, you have to be very specific with what you want, and stay involved during the project, to be sure the results are what you want.
This is *really* great advice. Standards are good, but it pays to have due-diligence done about specific products and methods. To the OP: I witnessed a municipal fiber build-out, managed by someone in another department who had essentially zero networking experience. His consultants' all seemed experienced in conceptual layout, but not so much the specific physical details. While this project was basically a success, 99% of the difficulties had to do with physical access details, site remediation (power, racks, site-local cabling), and the specific fiber related equipment such as splice boxes and patch panels. For instance, we ended up with a 23" telco rack filled with 19" equipment and 23" to 19" converter panels. General tidiness; a contractor left a large splice-box laying on the floor in the midst of a slack-spool instead of wall or rack mounting. Another contractor developed a spider's nest of wiring in our server room instead of structured cabling. Specifying exact rack sizes, specific cable management, mounting locations, etc... would have helped a lot. Photos of the specific areas would have helped immensely. Some of the delivered patch panels were of low quality (many of the connectors were faulty, requiring extra labor to clean and re-polish). Caveat emptor! Find what the good brands are and specify (maybe others can comment here). Go take a look at vendor websites like Middle Atlantic and see what options are out there. Some things are just easier and more convenient to use. The devil is in the details. A building-to-building connection is clearly easier than lighting up a city but you will still be stuck with what you get. You can never plan enough. ~JasonG