The only way to do that is to never carry the gun. All carry methods will put wear on the finish.

But if you want to minimize the wear, look for a holster with smooth leather on the inside and molded specifically for your gun, and clean out the holster periodically. Some people suggest suede lining because it's soft, but suede can trap dust and dirt, which will then abrade your gun's finish. And the reason for a tightly molded holster is that it will minimize movement of the gun in the holster, which would result in wear-causing friction.

Some people have had good results applying wax to their guns' finish, but I've never tried that. I expect finish wear on any gun I carry in a holster.