Cooking a meal for more than you're used to can seem like a daunting task. I've been using Pinterest for years to help make the process a little easier and now have it down to a science.
Before you start, consider the following:
----Who is joining you? (ie. will there be children there? a picky aunt?)
----Do they have dietary restrictions? (gluten free, vegan, on Whole30?)
----What is the total guest count? (5 stuffed cornish hens is a lot easier than 20)
Next, decide what your overall theme will be:
----Fancy? Tacos? Family style? Deciding what general route you're taking will prevent you from creating a menu that doesn't make sense. Plus, once you start saving pins to your menu board, Pinterest will start giving you suggestions which makes things a lot easier.
Get on Pinterest, make a board specifically for this menu, and just start saving anything you think might work.
Once you've saved a decent amount of recipes, go back through and read the instructions and ingredient list to find out if it's even feasible to make what you've chosen and dwindle it down that way.
Don't keep a flatbread recipe that requires the dough to rise overnight if you know there's no way you're going to do that.
A good menu will consist of:
--Something refreshing and light (usually a brothy soup or a salad)
--At least two sides (one veg and one starch)
--Protein (fish, meat or vegan substitute)
Once you've gone through and deleted recipes that don't work and have a good menu planned, make a shopping list. I use the Evernote app.
Create sections so you're not in the store for an hour going back and forth.
--Herbs & Spices
A week or so before the meal, read back through the menu and directions of each recipe to see when you need to start prepping, the temp the oven needs to be, etc so you know exactly when to start making each portion (it's helpful to actually write out a timeline if your menu is more than a couple things).
Another tip: If you really want to try an intricate dish but have never made it before. Try making it for just your family a week or two beforehand. This way you can alter anything you may have done wrong and you'll feel more confident serving it the day of the bigger meal.