I've seen some really good tutorials on different maker's websites, but in the case of a fursuit head base you have two big options: resin masks and foam (fursuit makers, feel free to chime in on this one!)
If your doing a bodysuit you'll also want to make a duct tape dummy! The advice I have for that? Buy some painters clothes to cut through and use TWO DIFFERENT layers of masking tape in DIFFERENT COLORS. <3
If you're going to cut the leading edge of some fur, use a dog brush and brush it back against the flow before you cut. You'll have less fur trimmings to clean up and it will leave overhanging fur to cover up your seams.
Another way to get good cuts is to cut as close as you can to the backing, rather than opening up the scissors all the way and shearing off tufts of fur every time you close them.
I might go to a con soon and i was thinking about going to a local convention so i watched videos on how to make fursuit stuff and found this,also i made my fursona not too long ago so idk if i should make a partial suit for him yet but hey