Use a valid TLauncher account and log in
Open TLauncher settings
Enable the skin system in TLauncher
Upload or select your skin in the TLauncher skin section
Launch Minecraft through TLauncher, not the official launcher
Install a shader-compatible version of Minecraft
Install OptiFine or a shader mod for that version
Download and place your shader pack in the shaders folder
Open Minecraft settings
Enable shaders in Video Settings
Join a server or singleplayer world and verify the skin is visible
If the skin does not show, restart TLauncher and Minecraft
If the skin still does not show, make sure the skin is linked to your TLauncher profile
If the skin still does not show, check that your internet connection is working
If the skin still does not show, update TLauncher and OptiFine
If the skin still does not show, disable conflicting mods and try again