In regards to the shelter set up, this was very simply a tarp and a piece of polycro for the floor. If you're not sure polycro is basically just window insulation film. It's been my go to ground sheet for a while now. It pretty tough considering how thin and light it is. You can see the polycro in this image. Most importantly though this photo was from an overnighter, so it didn't really matter if things got damp. However, I was using a synthetic quilt, so even if it had got damp it would have stayed warmed and dried out easily.
Then in regards to mitigating dew, I chose a campsite that I knew would receive a decent breeze and the air would keep moving. I actually had to move in the middle of the night as the wind picked up way more than I thought it would.
Realistically you main weapons against dew when using a floorless or single wall shelter are ventilation and campsite selection. Always sleep as high up as you can. And avoid setting up on long grass/heavy veg where possible. Unless the dew is crazy heavy then you can get rid of most of it in the morning by just wiping your gear down with a towel. Beyond that you last line of defence is either a bivy bag or going back to a double wall shelter.