However, I should say one thing - keep at it. You clearly have ambition and drive, and you're already better than 90% of people who do pixel art for indie games and such. You can be great if you apply yourself. I recommend getting a profile on Pixelation and/or PixelJoint, they're sites specifically designed for pixel art. PixelJoint has weekly challenge contests, which is a great way to quickly improve your pixel art and force yourself out of your comfort zone.
Look up tutorials, and more importantly - look up great art, and try to analyze and learn techniques they use. Looking for great art, I recommend PixelJoint Hall of Fame, and some games that have great pixel art - Shovel Knight, Metal Slug (entire series), Owlboy, Iconoclasts, Legend of Princess, Spawn for SNES.