This is my "backard" airsoft field I am making in my grandparents ranch. It's a pretty good size, however it's great for my use (walmart airsoft guns). I'll be going over the field, fort, some games you can play, what to wear, how to make gear, and how to make teams.
Please leave comments if you have any questions or if you can think of any way to make my field better. I haven't started building mine, so any suggestions are welcome. Also, visit my website http://beginnerairsoft.yolasite.com/, where you can also write your own articles and reviews.
The sketch of the field above is for the area I'm using, about 400 by 250 feet and with a small group (2-3 people per team). As you can see, there are already a few natural and man-made barriers (trees, canopy, chicken coop), but the rest are what we are going to build for it. Just check out the image where you can read what the things represent and maybe you'll get some ideas.
If you found the trash bag cover thing confusing, it is basically two 4 ft. sticks stuck in the ground about 5 ft. apart with a trash bag attached to each side. This works OK with kinda low fps guns, but if your gun shoots fast and rips through the plastic, use a tarp or blanket instead.