I make various sizes of messenger bags. If they use a laptop or tablet, I make it that size and add a slightly padded inside pocket to hold it. I make the bag in a plain fabric (khaki, denim, etc) but, I like to use a cotton print on the inside that is special to them (fishing, soccer, food!). Make an adjustable strap that can be worn across the body. I have also made a smaller one to hold a cell phone and keys for a nephew who likes to take short hikes. (I lined it with a dog fabric because he hikes with his dogs.)