I have had some success for my snoring with the Somni Snore Guard. It's a convenient and cheap way of reducing snoring. It also reduces bad breath. I have also heard of people who have used it in conjunction with a nasal dilator with even more success.
There has been some research into the use of the somni snore guard and it does seem to be effective for those whose snoring comes from mouth breathing. I have read a BBC news story which suggested that the success might have been exagerated but I've heard that they are very popular and seem to be effective as a means of preventing snoring.
In effect it works just like a gum guard. It forces the wearer to breath through their nose instead of their mouth. There are a variety of ways of achieving this but, as I said, the Somni Snore Guard seems to be one of the more effective treatments and preventative measures.