paintin figures and there surroundings

A good way to do sandbags is to roll up a 'sausage' of epoxy putty (Milliput), then cut the sausage at regular intervals. The blade will squash the putty and give it the corners and tapered ends of the sandbags. Use a piece of fabric to squash the middle part of the sandbags (the fabric will leave some nice texture on the sandbags). With the Milliput still fresh, you then just add the bags onto your model/base, again using the cloth around your finger to squeeze the bags into the position around rocks, tools, or any other details sticking out of your model/base. Let dry (a couple of hours), then prime and paint.

In order to get the sausage not to stick to your fingers, use plenty of talcum/baby powder!

wht about in trenchemnts or like fox holes tyoe things

In order to do that on the cheap, use a block of expanded polystyrene, cut it to the shape of your base, then dig the material away from where the trench and holes will be. Next, use something like Paris plaster to cover the foam. Have everything ready to place into the fresh plaster though: grass, trees, rocks, bricks, tracks...

wht about clay

Don't know... never worked with clay (other than the Fimo/Sculpey type)

I found that super fine micro brushes help in adding detail to 1/35 figures.

Except I dont know what company makes them