To use for carrying slinging stones simply use a smaller gauge.
This is straightforward net making - no increases or decreases used.
Once my students can tie the sheet bend
http://pineapple.myfunforum.org/about551.html I have them make a simple net bag like this.
1. Using the chain start
http://pineapple.myfunforum.org/about950.html make a chain 16 meshes long. I used a gauge 1 1/2" wide
2. Make a panel 30 rows long.
3. On either side take a separate cord. Count down 5 rows and strung the cord through the side meshes (see top of photo). Tie the ends of the cord together (see bottom of photo).
4. Take a separaate cord and string it through the end meshes (see top of photo). Tie the ends of the cord together to form a loop (bottom of photo).
5. Hang the bag by these 2 end loops. Will hold a lot of onions or potatoes or whatever.