The best way I find in making sprites is to first find a battler for the sprite so you have good reference material... Then look through all the sprites within RPG Maker XP, find a few that suite your needs, like legs, body and head, Export all those you think you can take bits from...
Then is you have Photoshop import them in and Turn the mode from idex colour to RGB, open your battler, Cut up your sprites and build some thing that resembles the battlers as much as possible, using layers, each time you get an area correct. Move onto another layer for the next area, that way you wont upset your previous work...
Then use the colour picker tool to choose the colours from the battler to recolour your sprite, you can do this again on another layer.
Thats how I make mine... I am sure you will find other ways that will suite you.
Good luck