1. Photoshop is your friend, espescially when it comes to large areas of black. Stars are easy enough, just white dots with the brush tool. If you want more glowy-type stars, use the airbrush tool to create a soft white haze, then add a sharper center with the regular brush.
2. If the final image is going to be in color, then "space" can actually be a dark blue-black Bg with clouds of space gas, nebulae, stars and the like. Not just black with white dots.
3. You may wish to kep a thin white outline around all your characters or ships or whatever, to help break them apart from all that black space around them.
4. If you want to try something REALLY different, make your light souces very harsh and one or two-sided.