To start, all spriters should read this. It explains everything in a very easy to understand manner -
1. When using someone elses sprite, even as a reference you should give credit. This is vital if you want to continue spriting as once you've been called a leacher, its hard to get the support you need
2. When you save the image, save it as a .PNG (Portable Network Graphic). This keeps the image preserved without blurring it like a .Jpeg
3. It might take a long time to understand the whole concept. Just keep practicing as practicing is the only way you'll improve
What is a sprite?
A sprite is a graphical image used in programs like games. Remember those old 2D sidescroller or fighting games like Street Fighter and Kirby? Each image you see in that game is a sprite
What Program should you use?
The best and easiest program is actually MS Paint. It has all the tools you need for spriting, but if you want to try a different program you can use programs like Photoshop or Paint.Net or specialist programs like Graphics Gale which is specially made for spriting
What is CnC?
CnC is "Comments and Criticisms" where another user will tell you whats good/bad about your sprite and what you should do to improve it. Some of the CnC you recieve will be harsh but thats usually the best. If you adjust your sprite acording to CnC then you will end up with the best result possible
What style should I sprite?
There are too many styles to count, so find one that you like and try to emulate it. When you get used to spriting in that style you can try custom sprites and maybe even sheeting. Just remember to give credits
Credits to Alucard and Triv..