Hi! Nice little shop you got here. A few tips:

1) Never resize pokemon sprites. Many of the examples you have there are squished and/or stretched, which distorts the image and destroys it, basically. x)
2) Recolours are still supposed to maintain their sizes, and also where all the shades are meant to be. Such as this: See how the shades are still intact and in the same place, and the colour scheme works? Make sure you do that, and additionally, neeeeveeeerrrrr use Paint's default colours. x_x They are horrific. Make your own palettes or take them from other pokemon. :]
3) For retypes, add more than just a different colour scheme, to make it interesting. For example, this is a retype I did...probably a long time ago - can't remember when - where I added icy elements to the ninetales as well as changing the colour scheme.

Anyway, keep practicing, because spriting isn't that easy. x)

~SF.