If you find yourself tossing and turning in the night, it could be due to your mattress. The two most basic problems with mattresses are that they're either too firm or too soft. Firmness varies greatly from mattress to mattress, and is based on personal preference. If you prefer that your mattress be a little firmer, there are a few tricks that can help you achieve this.
Bed boards, as the name implies, are thin, solid boards that are specifically designed for making beds firmer. Insert the bed board in between your mattress and box spring for added support. If you don't want to purchase a bed board, you can create your own from plywood. Simply measure your box spring with a tape measure, and then purchase 3/8-inch plywood from the hardware store to match those dimensions minus 1 inch (you don't want it sticking out).
Over time, your mattress acquires dust and dead skin, which causes it to weigh down and sag. By flipping your mattress on a regular basis, you can prevent the sagging shape, which will help it to become firmer. Flipping it basically ensures that the mattress weighs down evenly on both sides, rather than just one side, which will cause an uncomfortable soft "U" shape. Flip your mattress upside-down, left-to-right and every way in between to create the most even weight distribution.
Take your mattress outside and beat it with a baseball bat. This will help to remove the dust, dead skin and other acquired particles. By removing dead weight from the mattress, you help to prevent it from sagging, which will in turn make it firmer.
Many standard metal frames come with support bars that go through the middle of the frame horizontally. This helps to maintain even support for king and queen size mattresses. If, however, you have one of these larger size mattresses, but you're lacking a middle support bar, your box spring and mattress could be sagging. In this case, you should purchase a standard support bar, or buy a new frame that has a support bar.
Mattress toppers are devices that rest on top of mattresses to add a layer of comfort. They cover the same surface area as a mattress, but they're much thinner, as they're only meant to rest on top of a regular mattress. Mattress toppers are made from a few different materials, including memory foam, latex foam and feathers. Add a firm mattress topper to your regular mattress for added support.