"Staging" for and hosting an all ages backyard party

Yes on the citronella and sun screen. Mow a couple of days before, don't mwater that day depends on how much you usually water and when. Citronella sure, sun screen yes, shady area for kids/toys. I'd also have http://www.nytimes.com/2013/07/16/science/a-low-tech-mosquito-deterrent.html?_r=0 blowing; keep airflow going and keep bugs and mosquitoes away. Markers for putting names on glasses, etc.

Those big citronella candles or torches are great. Stick them slightly out of the way so people don't have to chase their kids away from them -- behind a row of chairs adults will be sitting in, say. Lots of bug spray! One thing that has worked well here is two coolers -- one with assorted non-alcoholic beverages, and one with the beers and coolers. I have never ever hinted at "BYOB" and still people BYOB pretty regularly -- your friends may vary -- but even if you don't want and aren't serving wine, say, it's good to have glasses and corkscrews for it at the ready. And extra fridge space for the excess beer. Lots of ice. I don't like music; you can't hear it if there are very many people -- or, if you can hear it, it makes it hard to hear people. I put serve-yourself-a-plate-of-this food out inside near the nearest door -- I have used clean new plastic "under bed" storage boxes and filled them with ice and placed food in that -- and bring bowls of chips etc outside. Lots of little tables are better than one big table. My favourite yard party was a "grilled cheese party" with a boatload of cheeses, breads, and various fillings; people assembled them in the kitchen, and brought them outside where some panini presses were set up. Everybody ate really well, and I didn't have to do anything to serve stuff.

I've done these a lot. People have it. Bug spray in both the super-killer (DEET) and not-super-killer (skin-so-soft) varieties. Sunscreen for adults and children. Look for wasp nests and other weird insect populations and handle them ahead of time. Get rid of standing water that will become mosquito breeding grounds. Have a rain plan (cover) as well as a blinding sun plan (shade). If you're going to use paper plates/napkins, have a wind plan. Can be as simple as a rock that you put on a pile of napkins. Having drinks for adults/kids outside in a bucket with ice is always fun (lots of assorted juiceboxes and sodas/seltzers depending what people want) have a bin nearby to put recycling. Have an outdoor trash can/compost/whatever you do. Mark it clearly. Keep on top of emptying the trash. Even if your fridge has an icemaker, you'll want to purchase ice most likely. If you have birdfeeders, fill them. I usually think it's good to have some sit down tables outside (picnic table for the kids if you can work it, there are some nice folding ones you can get cheapish) for people to put food down and eat on. I'm a fan of music if you have some speakers (i.e. not just an iphone), but just backgroundy stuff. Some of this depends on your neighbors. Speaking of them, it's manners to let them know if you're having a biggish outdoor party and make sure you have a plan for how/where people will park if they don't all fit in your driveway. Kids tend to enjoy basic stuff like random bocce, soccer balls, big inflatable balls for the littler kids, beanbag tic tac toe. Less fun are longer games that require rules that need explaining (badminton, croquet) unless everyone is playing. I've found that some parents are really hands off with their kids at an outdoor event and some are less so. Make sure any kid hazards you have are well marked or cordoned off. If there are parts of the house that are off limits, mark that clearly. If you have babies attending, let parents know where they can change them.

For games, you can't go wrong with http://www.diynetwork.com/how-to/outdoors/structures/how-to-build-a-regulation-cornhole-set. Someone you know may already have a set they can bring.

For lighting, my friends use strands of Christmas twinkle lights, either white or colored. It's enough to see by, but not enough to blind people as they get used to the dark.

We never knew we had wasps until we hosted a barbecue. We'd played out on the deck for weeks and never seen but one or two stray flying bugs. So maybe bring out a plate of hot meat a few days ahead of time and see if you get swarmed? Then you'll still have time to hunt them down and get rid of them.

Yes to citronella candles and bug spray. Also heavy coasters or something else you can hold down napkins and light items with in case of a breeze. Kid games should be things that involve no projectiles or light ones - bubbles and bean bag/cornhole are good as others have mentioned. Also I went to a party once where they put these little smoldering incense sticks in the ground in the bush/plant bed areas and my 4 year old burned the shit of her hand when she touched it because it looked like a stick. So I vote no on those :-)

No water, and fresh-mowed grass leaks chlorophyll onto everybody's shoes, so I'd aim for a day or two ahead of time. Plenty of chairs or non-chair places to sit (logs, benches, etc) and tables to set food/drink on, but not necessarily as a table-and-chairs set. You're trying to recreate your living room (chairs, couches, end tables, coffee tables for everybody milling around) not your dining room (table with 8 chairs for 8 people and their meals).

Make sure you have enough places to sit. Though a lot of people are okay with sitting right down on the lawn, there are those who might have trouble getting back up, or are wearing nice clothes, or just prefer a chair. Also, places to set down food when they're seated. Balancing food and drinks in your lap can be a pain.