Hi, Keith.
I use precut bases from Litko (
http://www.litkoaero.com/) because I am too lazy to make my own. These are laser cut so they are 99% perfect when you line them against each other. They are also very resistant to warping.
After arranging the models on the base, I paint the base brown (I use GW's Beastial Brown or Foundry's Spearshaft Shade). After that's dry, I paint the base with watered down white glue and dip the base into a tin of fine brown flocking (actually I think it's called ballast - it's from Woodland Scenics). I usually let this dry overnight and highlight it the next day with Foundry's Spearshaft C.
My last step is to add random patches of static grass. I don't usually bother with filler to hide the metal miniature bases as the ballast does a fair job and the static grass can be strategically placed to hide the most obvious spots the ballast doesn't cover (a reminder: I am lazy).
I also add extra bits on some bases - a broken wagon wheel here, a stunted tree there - but I usually only go all out for command stands.
Here are shots of my ECW army:
http://www.quindia.com/studiogalleryecw.htm
Hope that helps!