I don't agree that it's always the best idea to modify off of existing sprites. I tried working off of some of Kristoffer's sprites, when I had the opportunity, and it was a disaster. His style is just not my style. Infact, I don't even really understand it. Sombre's is closer, but still *much* different, no matter how good I got. I could maybe work from them, but they'd look like a sloppy rip-off of his work, rather than anything of my own. Now I do agree that it's easier to get colors and looks right when you've got a set to work from, but just modifying existing sprites is blah... Ofcourse, it's a *lot* harder and more work intensive, and harder to match the style of the game exactly, but by the third Nation or so, you'll have a nice set of your own images to improve upon and modify, and it'll preserve your own artistic take on things a lot better. And-once again-*doing* is how you get better. This isn't oil painting, it's atleast as much skill and experience as it is any "natural talent".
Also, Edratman, I find that the better I get at drawing sprites, the less I actually switch between colors. I don't know why that is, but they seem to look cleaner with just strategic shading.
And Sombre, I don't know if you've checked them out recently, but I've updated quite a few of my sprites, and I think they're starting to look a little better. I've also taken your advice and finally managed to get the main picture in full resolution by using a free upload site-so thanks!
