In my case I chose not to add any washes, in all truthfulness because I haven't put a brush to a mini all day and i'm getting rather impatient to get to it! :>)
Really adding static grass and grass tufts is a matter of taste. However here are two extra points that I think are worth considering. In place of static grass I've started using the 2mm tall grass tufts. Why? Well, it simply stands more erect than static grass and is easier to dry brush if necessary. Which brings me on to point two; dry brushing the grass tufts.
In general I'd mix up a light yellowy green colour (make sure that it is light). I would then mix a further light by adding Vallejo Ivory. Then it's really just a case of lightly dry brushing the tops of the tufts but with a slightly less dry mix of paint. why? Well, the static grass is obviously not as hard a surface as a miniature and will take less pressure to add the paint.
And that's really about it.
I hope that you found something useful in these basing articles(?).
Bye for now.