All I can say is do what you want or what you think is good, my old one was a orange and purple person for 4 years.
Look at skins you like and take insparation.
Thats all I can really say!
Older versions only used what is now the upper half of the skin texture - you can simply crop the lower half off and it will work (which is what used to happen when you ran older versions until the skin server they used was shut down; presumably it detected the version and sent it a cropped version of a 64x64 skin if it was older than 1.8, which I believe still happens in 1.7.10, which uses the new skin server but still uses the old skin format):
Basically the poster didn't login to approve their date being transferred to new owners during a forum sale, and under EU laws (GDPR) their account was deleted along with all their posts