Hello, I would like to get into texture making but I don't know how to start I have made head texture in the past but I want to move onto full sets.

no offence but the default texture templates aren't the best especially the arms because for some reason if you mirror a texture from the left bicep to the right for some reason they're still uneven

so is there a better guide to use or some kind of trick to making everything line up correctly?

I got a graphic tablet today, it's a bamboo one that only cost around $50.00
I am using Paint.net but may update to GIMP. (I am just very familiar with Paint.net that's why I'm hesitant about changing)