How you can Help

Upload your art for the group not only on the groups DA site, but on all other groups that are relevant to that piece of work. It's a good way to get not only your artwork out there more, but also great advertising for the group.
Creating adoptables for the group. This could also be done by creating species that are only allowed to be played on this group, or by having adoptables up for a price or points, but if they want to join this group, or are already a member, thy only have too draw the character and come up with a backstory for it.
Telling all your friends. It's very helpful to spread the word by posting journals, or dropping comments on your friends pages that may be interested in this group.
Free art. Another good way to lure people in is by offering them some free art if they join up. Obviously you don't have to draw something for every new member, sometimes having a few slots for those first five (or so) who comment and join can have a free picture.