A relaxed body is essential for a sound sleep. This may sound like we're contradicting what we just said about our minds keeping us awake, but it's no contradiction. Eastern sciences (such as yoga) have known for thousands of years that the mind and body are connected (actually they're not just connected, they're one, but the idea that they're connected is sufficient for our purposes here.) So if the mind is not relaxed, the body is not relaxed. Conversely, the body has to be relaxed for the mind to be relaxed. It's a package deal.
So how do you relax your body? We've already mentioned milk, herbal teas, exercise, and avoiding caffeine. But there are techniques you can do directly with your body. Toe Wiggling is one of them.
Lie on your back (where you should be in the first place) and wiggle your toes up and down 12 times, wiggling the toes of both feet at the same time. This will relax your entire body, inside and out.
How does it work? According to the science of Reflexology -- which has been around in other cultures for thousands of years -- your feet are a kind of master control panel for the rest of your body. "Meridians" in the body -- which are those channels of energy treated by acupuncture -- end up in the feet. So the ends of those meridians in your feet connect with every organ and every part of your entire body.
When you wiggle your toes, you are stimulating -- and thus relaxing -- your entire body. (Incidentally, this is a good place to mention that you can be energized and relaxed at the same time. It's a matter of the quality of that energy. If it flows freely and smoothly, you will be relaxed. If the energy flow in your body is restricted or blocked, you will be tense. And toe wiggling helps to bring about a relaxing, free-flowing energy.)
Note: This same exercise is also great first thing in the morning before getting out of bed in order to energize the body.