This is probably my favourite part about Lego. Minifigures, tiny people twice as tall as gummi bears. There are thousands of them, but say you need a minifigure that you don't have, or is REALLY rare, or simply just DOES NOT EXIST. Minifigure customisation is the art of making new minifigures out of current minifigs, and other resources. If you have a few minifigs, and enough imagination, YOU CAN LITERALLY MAKE ANY CHARACTER.
There are loads of professional minifig customisers out there. Brickarms is a very popular company creating custom weapons and other war-type items, both fictional and based off of real life, made of ABS, the exact same plastic minifigs are made of, specifically designed for Lego minifigs. They don't sell them directly from their website, however, but you can get them at authorized Lego-related websites.
If you want your minifig's body parts to look different, you could order special custom-printed parts from companies like EclipseGrafx, get custom decals from companies like Brickstix, (Which makes easily removable stickers for Lego) get some paper-texture labels and draw your own, or even custom print/paint them. Today we'll look at option 3. You just need a pencil, colours and labels. ^ ^ ^ ^ You should probably get the measurements of the piece you're going to put a sticker on. This is also a good idea for making designs on bricks!
Want MOAR minifig fun? Head here or here!