Raking the Field
Proper raking reduces the formation of a grass lip on an infield edge. Always rake parallel to a grass edge not into it, and avoid pulling infield material into the grass edge. See the video below about proper raking around home plate. Same technique can be used around the mound.
Lining the Field
This video is a good primer for how to properly line a field. There is a lining machine in the press box behind the Varsity field. There should be one in the equipment box at the Freshman field. Ropes for lining can also be found in the equipment boxes. The batters box template will be in the press box.
NEVER SWEEP OR PUSH WATER FROM THE INFIELD ONTO GRASSY AREAS. THIS WILL DEPLETE THE INFIELD OF DIRT AND DRYING AGENT AND CAUSE LIPS TO FORM. You can try to rake out the wet areas, again being careful to not rake from the infield to the grass areas. Hand pumps can also be effective.