Display short vintage appliances, such as a waffle iron or a sandwich griddle, on top of a thick book, such as a telephone book or encyclopedia. This lifts it up over any wood lip that might block part of the appliance.
Stagger the heights of similar sized appliances, by setting one on top of a thin book or one with a medium thickness. This creates added interest.
Add variety to the display by offsetting the square or rectangular vintage appliances with old mixing bowls placed in between two objects. Another option is to hang antique kitchen gadgets in between the appliances, such as an egg beater, a pastry blender or an antique citrus juicer. Use nails to mount them on the wall or roll up small balls of museum putty to attach the object to the wall.
Wrap a piece of fabric around a piece of floral foam or a thick piece of a foam sheet. Tape the edges underneath the foam just as you would a gift. Use this to raise the vintage appliance up on a soffit area that has a decorative railing that you can see through.
Tilt the vintage appliance forward if it is flat and has a decorative top you want to display. Set a book or another thick object under the back half of the appliance. This is appropriate if you have some kind of railing that prevents the appliance from sliding to the floor.
Position tall appliances next to shorter ones. For instance, display a vintage coffee maker next to an electric skillet. This creates variety and makes the collection more noticeable.