There are grass strips and grass strips. Barton for example might be grass, but you really do need to listen to the tower and lining up to wait is often the norm.
Off a farm strip, I see it as one continuous movement, keeping momemtum going when at the threshold, never stopping and running the risk of getting stuck. As has been suggested elsewhere, have a marker on the r/w which indicates the half way point. Know when to abort.
Equally, I do not deploy flap until desired speed has been reached (reduces drag in the roll). Once deployed, get it up sharpish and into the ground effect (for the low wing in particular), once required speed achieved for flight, up you go - for real.
On landing, you must nail the speed early. Always easier to add on a few knots.
Cardinal rule, use an instructor for the first few times.
The Wombat