A DeviantArt group, is a subdivision of Deviantart users dedicated to an especific tipe of art, or an especific goal here in Deviant.
There are many many types, and a wide range to choose.
im prety sure ther should be a group dedicated to portraits and that kind of things.
These are some examples:
Normaly, post your deviations in a group, grants you with a lot more of views, because your deviations is placed in comunity of deviants that want to see the type of art that is displayed on that especific group.
Many deviations fit in many groups. So people beging to follow your artwork. Is a great way to let you know as an artist. Give it a try.