How can I stop snoring at night using OTC products?

Hard to say. Avoid sleeping on your back, dont drink alcohol at night, avoid smoking, and lose weight -all of these can help decrease snoring. If you snore and stop breathing at night, you need to see sleep specialist to rule out sleep apnea. But otherwise people snore for multiple reasons (could be nose related vs palate vs tongue vs a combination of these) so there isnt one answer to your question.
Exercise. There are various devices. The best otc approach is regular exercise to loose weight and decrease the amount of redundant soft tissue in your posterior pharynx. (back of your throat).