Plants young fruit trees, especially mulberries, and the lil buggers will be in your yard to eat them in no time
In my neck of the woods, I normally see them in mowed areas, along roads. It seems like they feed at the edge of open areas more than in the middle of brambles/bushes.
I walk my dogs around the edge of my property daily to help keep groundhogs out of my yard, so making sure to keep dogs out of the place you want them would also help.