After my son Logan died I found that I was desperate to find ways for him to "leave his mark" on this earth, physically. One of the things that I did was to plant a tree in is honor in a local park. You can see that here. I also had a name print done and had his name written in the sand by Carly (many parents print this photo off and hang it on their wall) and had a necklace made with his name and Angelversary on it by a fellow DBM. There are so many ways in which we can memorialize our children. Here are a few more:
Memory Blanket (from your childs clothes)
Have your childs portrait Sketched
Angel Pics (free Photo Retouching for Stillborn Babies)
Some folks like to plant gardens or a specific plant, make stepping stones, create a water pond or have an area put aside especially for the belongings of their angel baby. Many local places allow you to purchase bricks or plaques in memory or your child(ren), places like your local library, school, activity center, church or park. Here are a few other nice ideas. If you did something, bought something, or heard about something that you think would be beneficial for another grieving family, please do share.