You may want to check out the various Pixel Art forum's for additional tutorials and advice they can give, such as Pixeljoint (some good tutorials here), GMPixel, and Pixelation forums.

There's also a really good tutorial that includes some Ragnarok'esk sprites here, unfortunetly its written in japanese i think (translated through google though), may still give you a good idea on some aspects of it.

I don't know what your current skill level is artistically, but the first thing you should do is learn to draw. Pixel art is harder than more traditional "analog" artforms because you're more limited, both in palette and in resolution. You don't want to be learning fundamentals of structure, composition, and perspective on a computer; use a pencil instead.

Take a few months to practice drawing, and I mean seriously practice it, and then you should have about enough skill to at least get a start on pixel art. Join one of the dedicated pixel art communities (GD.net is very generalized; you won't get as useful of feedback here), lurk a lot, look at other peoples' work, and do your best to make your own. Again, practice for months and you'll eventually be making something presentable.

The emphasis here is on practicing. You aren't going to be able to just up and make new models for free; otherwise game artists wouldn't be employable. It takes a lot of hard work to make professional-looking graphics.