My DH and I are convinced that something happens when people get together in one another's home -- friendships deepen, and the world becomes a little brighter and more welcoming.
I'd encourage you to choose a "format" that works for your family. Do you want to do cocktail parties? Game parties? Movie showings (we did one for the new Sherlock broadcast)?
Next, I choose a menu or two and use if over and over. Do you make a great Salmon? Go for it! Do you have a favorite restaurant that caters? Bring the food in, and concentrate on a homemade dessert and great coffee or wine. In winter, my "go to" meal:
2 soups
homemade bread or biscuits
pineapple or apple cake and ice cream
veg plate, hummus, chips and salsa, fruit plate
Simple, eh? Since I moved last Summer, part of my goal is to encourage new friends to share their homes. I've learned if I'm too "fancy," they're afraid to have me over! The smell of simmering soup and homemade bread is nurturing and friendly. That's how we want people to feel at our house. The bonus? My family eats the leftovers happily!
When I do "fancy" I usually keep the main course easy -- a big piece of fish (I don't have lots of luck with this) or a turkey or ham. I focus on some make-ahead fancy sides --- gratins and veggie casseroles, fancy salads, etc. I also have enjoyed doing small and elegant "tea party" foods for book group gatherings. Many of these sorts of 'finger foods" can be made ahead, and a lot of the book club crowd likes to pitch in with their own favorites.
Since you're an introvert, you could start with smaller gatherings. A couple of families, or a group of 6-10 can be festive, but not overwhelming. If you're not a late night person, don't forget the possibility of a brunch or lunch party.
Finally -- enlist your party loving son and husband! I find that this makes everything easier --- particularly the clean up. My DH does the inviting (Yes, he calls people and sets things up), and preps the house. I do the menu and event planning and cooking, with some help from DD. DS is on clean up crew!
Let us know how it goes!