Patching and Plastering - Drywall repairs

Is there a trick to hiding repairs to drywall? I fill in nail holes and such then sand smooth but the spots seem to show after painting depending on the way the light hits the wall, how do you match the texture? Thanks!

Couple different issues here. First is that you want to cover the spot with a sealing primer first, or you will see the patch because the spackle absorbed the paint differently than the surrounding wall. Second is that it helps to know what the texture is in the first place. If it's just roller nap, painting with the same nap roller should do it. If it's and orange peel or knockdown texture, you'll probably have to texture the surface to make it match.

To add to mitch's advice - mud shrinks as it dries so you need to be sure the repair is level before priming. Textures can usually be replicated with thinned down joint compound. Orange peel and roller stipple can be done with thin mud applied with a sponge - small areas only.