how to make sims 1 custom skins???

[littlesausage]

I keep seeing these adorable anime skins all over the internet and i want to know how to make those. there too cute. i want to make my own. how do i go about doing this?  

[Happy Tragedy]

They have tutorials on ModTheSims2.com, and you can always try googling tutorials for making skins.
Skin Making can be a little difficult, so if you wanted something in particular, you can ask people who are open for requests and make skins. (There are some people on MTS2)