Paint fumes will go away on their own, of course, but if you don't want to have them lingering you can get rid of the odor with a simple bucket of water and a handful of lemons.
If you don't own a bucket, try using your largest pot for the stove (and change it frequently) and add a few lemon slices inside. Not only will the lemons give you a natural fresh smell, but the water will actually soak up the paint fumes your diy project left behind.
Change your water once a day until fumes are gone, but in most single rooms this trick can work almost overnight! Brilliant!