1. there is good food
2. guests are comfortable, and
3. that you have fun too.
So those are the essential things but you have to break them down into a to-do list:
1. there is good food
The menu is interesting (but manageable) and the food stays warm.
2. guests are comfy
There are adequate spots for guests to sit and/or hang out and chat, and they are not getting bit by mosquitoes. Also, guests should be able to get food and drink when they want it and how to do so should be intuitive. Lastly, your little guests should be comfy and happy too and should have something to occupy them.
3. you have fun too
You can relax and enjoy the party when you're not stressing out. So take care of the things that would stress you out: get the house in order; think through the details (plan, mentally diagram and do stuff ahead of time); make sure the food situation is under control; and have a game plan if it rains on this giant outdoor party .
menu is interesting but manageable
I generally pick a theme and cook a few things the morning of the party and combine it with make-ahead dishes and catered dishes from a restaurant. With regard to catering, don't just go to restaurants that have a set catering menu. If you find some hole-in-the-wall place that you really like, I bet they would make a bulk to-go order of your favorite dish to take away.
sample menu: superhero fiesta
Cuban Ropa Vieja Shredded beef (crock pot, overnight)
Pork Carnitas (crock pot, overnight)
Spinach Enchiladas (catered)
Cheese Quesadilla (catered)
Mexican Rice, Pinto Beans & Guacamole (catered)
Quinoa and Black Beans (made the morning of)
Southwestern Chopped Salad with cilantro lime dressing (dressing made 2 days before)
Homemade Caesar Salad (dressing made 2 days before)
Sopapilla Cheesecake (made day before)
Tres Leches Birthday Cake (from bakery)
Fruit Salad with Cinnamon Sugar Pita Chips (fruit sliced the night before)
and this is how you keep the food warm
guests are comfy
make it intuitive - how do guests get food and drink
what if it rains?
what to do with kids?
how to string lanterns in your backyard
2. Bury the poles in exposed dirt where possible, e.g. garden areas, so you don't end up digging big holes in your yard. Bury the poles 6-12 inches.
3. If you want to stand a pole in a grassy area, use a concrete block like this to stand the pole up.
4. Space the poles evenly.
5. String the lanterns along the poles using a staple gun to affix the wires to the poles.
6. Use an extension cord to plug the lanterns into an outside outlet.
(We bought our lanterns during a 75% off end-of-summer clearance at World Market. Here are similar ones.)