Sure. I find it best to keep it simple, use a decent palette like DB16 or Arne16, block in your shapes, and then add details. Constraints are your friend, especially when starting out. See what you can do with 4 shades of grey in 32x32 pixels .. for example can you draw a set of 8 different x-men within those constraints?

When you get to higher resolutions you need to think more about what the actual pixels are doing, are they jagged, are they banding or blurring, etc. A decent tutorial which covers those concepts is:

http://www.pixeljoint.com/forum/forum_posts.asp?TID=11299

Understanding form and colour and shape and all those things from visual art is important for a lot of bigger pieces, but the nice thing in pixel art is that if you work in a low resolution it's easy to keep tweaking until it looks good. I did a lot of adjusting earlier on.

There are so many different styles of pixel art -- so browse Pixel Joint's gallery or the @Pixel_Dailies account until you find one that resonates. Copy and paste the image into your editor and then start pulling it apart to understand how it works. We did quite a few of these studies, and I found that artists like JunkBoy, AbyssWolf, and Mmro Tarius are especially instructive.

Good luck and I might see you over on Pixel Dailies sometime.