Make sure the carts contain little plastic 'jars' that are full of a topdress mix. A small decal placed in the cart that says something like "Please repair all ball marks on greens and fairways to preserve to the course" Par 3's should have a little wooden box on the tee box full of topdress with a little sign.
Hand out complimentary plastic repair tools with the courses logo. Everyone I have played with always fixed ball marks on the green. It is considered bad etiquette to not do so. About 30% of the guys don't repair divots in the fairways and tees though.
Change the pin locations daily. You can try adding one of those giant industrial fans to the softer greens.
There always seems to be a disconnect with the people working the cart barn and the maint crew. The people that work the cart barn never seem to want to get there hands dirty. I think when it is slow they should send someone out to repair ball marks on the greens.