More than with tarmac you need to be aware of the state of the runway. Not just if it s wet and slippery, but it can also have potholes, be more undulating. I remember many years ago at Ipswich you were told to land left or right of the centre line because of bogs.
Always keep the weight of the nose, both on taxi, take off and landing to avoid prop strikes.
Grass is substantially more slippery when wet than tarmac, so be aware of morning dew, not just rain. So never break harder than you have to. I like to dump flap immediately after touchdown and only apply brakes when there is zero lift left, with a gentle pumping action with the control column pulled well back