Know the sports or other events that will take place on your field, the number of events, and the time of year when the field will be used the most.
Know the physical makeup of your field before starting construction. Test the soil for sand, silt, and clay content.
How many rainouts can your program tolerate? Reduce the number of rainouts by rebuilding your field to drain well.
Monitor the rough grade of your field. It should be plus or minus 1/2" from the final grade. You also want a clean rough grade, remove any rocks or debris.
A laser grader can provide an accurate final grade in several planes. If you can't use a laser, stake the field on 25 foot centers.
For irrigation, you can trench or pull it. If you trench, watch out for settling. Also test your irrigation system before seeding or sodding.
Beware of having a 'road builder' to construct your turf sports field, especially a contractor who proposes using a sheeps-foot roller that will compact the field so severely that the turf grass will not be able to establish strong roots.