First, get a timer from Wal-Mart (Or your other preferred shopping place). When you set it to come on a periodic times throughout the day, you maximize the scent. It takes no more than 30 minutes to melt it. Leave it on 30-60 minutes and then have it shut off. You can have it come on a the best time for your enjoyment! I set mine to come on just before I get home from work so I walk into a room that smells great - and I know it hasn't been filling the room all day.
Second, switch out your scents periodically. This helps combat the natural anosmia that we get when exposed to a certain scent for a long amount of time. (e.g. I had Peach a la Mode going for over 24 hours, I could still smell it when I came home [albeit more faintly] but my brother, who was home all day, couldn't smell it anymore.) You can save the wax you take out and then try it again after you get tired of the "new" scent.
Third, turn off your warmers when you're cooking. The bacon that you're cooking is going to win the contest :) You will want it to fight odors that remain after supper is almost ready.
I hope these suggestions are helpful! Do you have other ideas? Please share them in the comments below.