Covering the windows of the incubator with something like a towel to keep it dark inside can help keep the already-hatched ones calmer. (Under a hen is dark, so darkness clearly does not prevent chicks from hatching!)
At some point, it makes sense to remove the already-hatched chicks from the incubator. Obviously, do it quickly--have a box sitting right there to move the chicks into, so you don't keep the incubator open longer than needed.
I would plan on removing hatched chicks once or twice a day, unless someone else comes along with a better suggestion. When you do remove them, take out wet ones and dry ones, as long as they're completely free of their eggs--they can dry off in the brooder, as long as it's warm enough and free of major drafts. (I think they settle down and sleep better in the brooder, rather than stumbling around in the incubator, but that's based on possibly-inaccurate memories from a long time ago.)
