I think it depend on what kind of graphics you are looking for. People usually go with pixelart in indie development.
If you are looking for this kind of graphics I would recommend going to deviantart.com and searching "pixelart" or "game pixelart". It will spits out countless game sprites. Download some of them and study them at 300% zoom. Some people say its good to read some books but I would say practice makes perfect. So try some of these:
Pixelart is not THAT time consuming. But if you are looking for some better/complex graphics. I would say choose if you want to be a coder or a designer. Making game assets itsis very time consuming, and it will make your progress much slower. I would recommend hiring someone OR if you don't have enough money but you have the enthusiasm. Find somebody who shares the enthusiasm and start a small "indie studio" and cooperate.