Using a sealant will allow you to add another layer of protection to your paint and this will also increase the durability of the wax as well. The sealant creates a stronger bond for the wax than it would to the paint, which means that it will last longer.
Sealants are usually in the same form as liquid waxes and can be both applied and removed in the exact same manor.
Another tip is to layer up the wax. You can do this by adding a layer once the wax has cured. Some manufacturers recommend that you wait up to 24 hours between adding layers for a premium bond.