This tutorial will give you a good idea of how to make a starfield, without having those monochrome looking stars.
1.First of all create your image, size doesn't matter (well, it actually does. If your using a small canvas, make sure the brush size is smaller, a bigger canvas an you make the brush a tad larger).
2. press D (set's your colors back to black and white) now fill the image with black (ctrl + backspace).
3. Now you have your space, but no stars. Make a new layer (ctrl + shift + n) and call it stars, pick out one of the preset star brushes and set it to theese settings:
Set your opacity to 50% and size to around 10-15 and start brushing a FEW stars. Then set it to 75% and draw a few more, and last 100%. If you think their to dark, go image->adjustments->levels and move the little white arrow to the left. You should now have something like this:
Last step would be taking out your brush, resseting it, and set it to 1 pixel, 100% opacity and 0 % hardness. Then start painting a few dots for some really bright stars. **Important** Don't over do this!!!!
Now the background for your future space scene is set!
(Note: This is my first tutorial, so bare with me)
