Okay, for starters, you need to choose a medium: You can draw it with pencils on paper, ink, color pencils, painting, crayons, or go direcly into digital painting (that pretty much mimic all the previous options. Yes, I have a digital painting program. I may send a copy if anyone is interested)
By what I saw of your drawings, you seens to like working with colors, but its aways good to practice a bit with pencil on paper.
For drawing, I use either Photoshop, or a program called Open Canvas, that is a small drawing program that allows people to get online to chat and draw. But now that I got a scanner, I'll do more drawings on paper (that are about 200% better, IMO).
For coloring, I use Photoshop, with some coloring tricks I learnt in all the time I was scannerless.
Here's a tutorial:
http://mestredosmagos.deviantart.com/gallery/Just look for the icons with the "How to color".
And remember to aways check famous artist's works to see how they do some images, so you can learn, but dont copy anything direcly.
Here's my help for today.
PS: I know how muscles are hard to draw... lol