First, toast the buns well. Then apply burger sauce or mayonnaise on both halves of the bun. The sauce contains oil which prevents the moisture from seeping into the buns. Place the salad leaf. On top of that goes your patty. Place raw onions or tomato slices and cover from the top bun. Insert a toothpick to hold everything together. If you have any other ingredient like fried onions or mango salsa etc. place it on top of the salad leaf. This way nothing falls when you take the bite.