None of my approach is new, I've just copied the work of others, but as requested several times, here is my approach. The unit being based is the SYW Swedish Blau Hussars, plus a few other bits.
Step 1 glue the figures down to a base. I'm still using mounting card and fixing the figures using a hot glue gun
Step 2 I paint neat PVA all over the base and then dip in in my sand/crushed kitty litter mix.
Step 3 Brush off all the loose basing material. A lot of the larger bits come off at this stage and might leave a bare area, if so just repeat step 2 on the area.
Then paint dilute PVA over the whole base, this ensures the basing material is firmly fixed
Step 4 - apply the base colour for the terrain. for most of my figures I use a chocolate brown colour, normally using a tester pot of ordinary emulsion paint and diluting enough so it flows easily. This is just slopped onto the base just being carefully where it meets the figure
Step 5 - Highlighting the surface. This is the step where I have the most difficulty with ordinary emulsion paint, some of them just will not dry-brush, but I haven't found out how to distinguish which is which. Normally I use a dry-stone colour for the highlight
Step 6 (Final) Once the dry brushing is dry, it's back to the neat PVA again, added in a random pattern and then the base is dipped into static grass and left to dry.
1) For infantry units where the base is quite cluttered I quite often paint and texture the figures based before gluing the figures onto the mounting card as it is easier (and safer) than trying to do it all in one step.
2) Make sure that you leave adequate time for drying between the stages I normally leave about 4 hours plus
3) Make sure all gloss and metallic surfaces are completely dry before starting otherwise the basing material gets attracted to them. In order to show the steps I left painting the swords until after I finished basing
4) Crushed kitty litter is produced by putting ordinary kitty litter in a plastic bag and hitting it with a wooden mallet or similar until it is sufficiently fine.
I hope this helps