Don't necessarily look out the corner of your eye, but just slightly off the side of the object.
The crosses in these illustrations shows where I mean.
In the 1st image, Top section shows what a DSO looks when looking at the yellow cross.
Bottom section shows the same DSO if you look where the yellow cross is.
(it doesn't work on this scale so don't expect to see the galaxy brighter by looking at the cross in this example)
In the 2nd image I give some examples of some places to look in the eyepice. The object in the centre will appear brighter when looking at the white crosses.
(again, not in this sample, only in the real eyepice) 