1. For starters, pretend like you're a visitor in your own home when you walk in to determine what the smell is.
2. It might sound weird, but you should wash your walls once or twice a year, since they're probably absorbing whatever the stench is.
3. If you're cooking, make sure you use your vent hood.
4. Buy some air sponges to absorb any stray scents you don't want to linger.
5. Clean out your fridge regularly, especially if it has an ice maker.
6. If you have a cat, get an automatic litter box to avoid the dreaded feline odor.
7. Use an essential oil diffuser/humidifier to get good, clean smells circulating.
8. In a pinch, opt for Ozium to actually sanitize the air around you.
9. Open your windows to let some fresh air circulate.
10. Take out the garbage every single day.
11. Wash your sheets regularly, but also deodorize your bed/bedding often, too.
12. Invest in a HEPA air filter to sanitize and purify all that gnarly air.
13. Make a simmer pot — aka a DIY air freshener — with items you probably already own.
14. Or put a teaspoon of vanilla in the oven for 30 minutes to feel like you live in a warm, clean bakery.
15. Try using wax melts instead of candles if you're worried about burning your house down.
16. Spring for a carpet shampooer for when a regular old vacuum just doesn't do the trick.
17. Or use a steam cleaner to really zap bad odors and stains out of your stuff.
All tips sourced from this Reddit thread and this one.
Some responses have been lightly edited for length or clarity.