I recently made a few swampy hex tiles to fit my 3" hex mat. I decided to make them totally flat so that it would be easier to put figures on top of them. Here are some pictures.
They are made out of clear, heavy report cover material. The blue, green and brown stuff is painted onto the reverse side. I painted those colors at the same time so that the wet paint would blend a bit. Once dried I painted the top side with gloss acrylic medium to give it a wet look. Finally I painted the flat green areas. If you look closely there is a bit of depth because of the thickness of the plastic report cover.
Meanwhile, painting continues for the 44th NY infantry. I've have finished the block colors and then I did my dirt-glaze layer. Dirt glaze is similar to "the dip" method. The difference is that I use matte acrylic medium mixed with some brown and black ink. This stuff has the consistency of acrylic paint, but it dries to be a very transparent dingy color. I use a brush to apply a thin coat all over the model except for the skin, because I have already shaded the flesh areas. The dirt glaze naturally fills recesses in the model and it dries nicely. Sorry for the poor picture.