1.) Get out of bed (because I know that's where you most likely are if you're homesick), get a shower, and get out of your flat/apartment/townhouse/dorm room/etc. Yes, I know it's much easier to just stay in your pajamas and wallow all day long until you can go back to sleep in hopes of waking up the next morning cured. But the truth of the matter is, you'll just build up more feelings of loneliness and homesickness that way. Trust me, I know. There have been several days here in Rome (or back home at my university) where I've done exactly what I just told you not to do, and it has not helped. So now, when I begin to feel the symptoms of being homesick, I get up and get going. It gets me away from the doom and gloom of my bed and out into fresh air.