>>3241738Bring your smartphone/tablet and show them some pictures of their characters. That will give them a clue to pose, and you will know what to frame.
Also remember that the costume is important in the cosplay. Take everything, from toe to head. Add some close shots after.
The background is important, have it clean and simple rather than busy. A grey wall is better than a tree.
ISO between 400 and 800, avoid the direct sunlight and bokeh whoring.