To be honest the armor and mobs is the most dificult textures to make good.
Thinking about the source it has a 128x64 px texture. the model i made is at 4096x2048px. so when i export it back into the game it will be a bit lower in quality tho still look good.
The leather armor is the first armorset that im redoing. I wasnt happy with the mark.1 version i did.
(ignore the missing helmet and the reflective head. its just how the software I use displays the minecraft model)