Any Tips?

     I t hink  you're off to a good start.  You can vary the smoothness of the terrain by laying down some thinned white glue and then sprinkling ground cover on top.  I usually start with good ol' real dirt, sifted through an old kitchen strainer.  Areas you want to be really smooth you can leave alone, without any dirt on them, and areas  you want to have more texture you can do the dirt thing.  Then you can start adding grass.  When you paint, you can do the whole thing in varying earth tones, and then what I would do is paint the tread marks in a darker earth tone to simulate wetter ground that's been pressed down by the weight of the vehicle.  I'm no pro, but that's my .02.

looks pretty good so far. i am using celluclay on my dio too (also my first) and it worked pretty well....i put mine on a tad too thick though so it took about a week and a half to dry. the only suggestion i would have is make some shallow ditches on the sides of the road (bearing in mind that german tanks, especially the tiger and king tiger, took up about 3/4 of the road) to make it look more like a road than a field. my very first dio base i made i used sand mixed with white glue and some water and i kinda botched that: i tried to make a road with ditches but it looked more like an eleveted dike in Holland instead of a road in russia.

the pic below is the second attempt: i used celluclay, a craft store winter tree, and woodland scenics grass and snow. i painted the mud with brown enamel (enamel wont re-soften celluclay like acrylics will and it also covers the grey color alot better in enamel)

 regards, Logan