I know it may be hard to hear but you definitely need to learn some patience. I struggled with this as well, and once I decided to let myself spend days, or weeks (yet to get to the month mark) on a piece I found myself feeling much more accomplished and proud of my work! Try creating a piece of art slowly, just do it once, and see how you feel about it... you may be pleasantly surprised and (like me) never look back.
I recommend getting formally aquatinted with layers in Photoshop or GIMP (if you have no already), layer mechanics are simple but fundamental to drawing of course. Play around with overlays etc, and never draw on the background layer :P. Start with something easy, pick your favourite Pokemon and try to draw it slightly different than an image you find. Start by making a messy layer with just shapes of what the image looks like, make a new layer, and turn down the opacity on your first layer, and start drawing your outline using the shape to help you. You may need to keep making layers and perfecting your outline, be patient and remember that a good set of lines paves the way for a fantastic drawing. You need it as a foundation and you can't make something look better just by colouring (imo). Hide the layers you don't need (keeping only the final outline layer) and start with your basic colours. Use a clipping mask to shade, highlight etc, and play around with it!
I agree with another person in this thread that you learn by doing, but technique tutorials are absolutely well worth your time! Check out deviantArt for these sorts of things, and browse other artist's work. Everyone is mortally afraid of copying someone/being copied there but in all honestly if you learn something by looking at someone else's work it's fine. Just don't out right take credit for their work of course :P.
Anyway, I hope this helps a bit, feel free to leave me a VM if you want anything explained more or have any questions. I am not perfect of course and I have a lot to learn in terms of digital art, but I sure have a lot to share as well. :) Good luck!