Prevention of snoring includes:
- Lose weight if you are overweight
- Avoid alcohol before bedtime.
- Avoid sleeping flat on your back.
- Avoid muscle relaxants.
- Avoid sedatives.
- Avoid sleeping pills.
- Avoid narcotic pain medication
- Take oral antihistamines for snoring if you have allergies:
PubMed Snoring References
- Kohler M, Bloch KE, Stradling JR. The role of the nose in the pathogenesis of obstructive sleep apnoea and snoring. Eur Respir J. 2007 Dec;30(6):1208-15. 
- Norman D, Loredo JS. Obstructive sleep apnea in older adults. Clin Geriatr Med. 2008 Feb;24(1):151-65, ix.