Use an American Cambered Grip bar or American Gridiron bar ( https://www.elitefts.com/shop/bars-weights/specialty-bars.html ). Grab the bar so your pinkies are inside of your thumbs and do shrugs. When you are shrugging don't focus on your traps. Focus on the bottom angle of your shoulder blade moving up and down. This will help train the lower part of the trap which is often neglected. The yoke will take care of itself.