Whether your company is just switching to an open office plan or has had one in place for a while, it's always useful to discuss, and then implement, a few general rules for appropriate behavior. First, schedule a meeting so you can get everyone's input on some of the most distracting, unwelcome behaviors. Don't assume you know what they are. Although certain issues are common in open offices — loud music, overhearing conversations — others might be more particular to your office. Make sure no one feels targeted during the discussion. If a lot of you dislike Brianna's smelly egg salad sandwiches, don't suggest banning egg salad sandwiches. Instead, mention strong-smelling foods as a distraction. Try to get the group to agree on a few basic no-nos, then test out the "ban."
If the group largely adheres to the new rules, great. You've just eliminated some distractions. Schedule another meeting in a few weeks to see if there are any new issues to discuss, or rules to add. If there's little adherence, and no backup from the boss, your office probably isn't conducive to the concept. (Luckily, we've got nine more coping mechanisms that might work.)