My hunting partner of over 45 years and I started our careers on ruffed and blue grouse. Back in the day logging clear-cuts that had a good start of pioneer growth were always a good spot.
Grouse will also feed on the clover growing on old logging roads. Once you get one, check the crop at the base of the neck to see what they're feeding on.
If you can find a little stream running through a logged area check it out in the late afternoon or evening.
.22's are great if you're looking for a sporting hunt and sporting shooting. If you're after meat it takes little skill to shoot them on the ground or out of a tree with a shotgun. However, if you get them into the air you'll not find sportier shotgunning.
If the grouse is in a tree or on the wing when hit pay close attention to where it falls or you could spend as much time looking for it after the shot as you did before.
A head shot or one that disrupts the nervous system quickly will set up a lot of rapid reflex flapping that makes the bird easy to find. If you hear/see this fluttering don't worry, the bird doesn't need another shot.
I found skeet loads are perfect for ruffed grouse regardless of gauge. The smaller #9 shot seems to slip through the feathers and doesn't carry them into the meat.
Late season tracking them in the snow is great sport.
As Cat showed, hunting them with a good dog makes for more and faster action, but that comes later.