Since you have built up a year long relationship with the local crossing guard, it's important to remember to thank him or her everyday verbally. They do appreciate it and it's easy to do.
If you don't already know their name, you can find it out by looking in the school directory. Personalize a thank you card. This card should be handwritten by your child, since he or she is the reason this crossing guard works so hard everyday! They love kids!
Inside the card, add a gift card or gift certificate to Starbucks or Jamba Juice, or perhaps See's Candies. It's a small token, but they will LOVE it, especially on the last day of school! Kid's artwork is another nice touch.
Cut some flowers from your garden and make a small bouquet to give to the crossing guard. It's another small gesture, but one that shows your appreciation to their service to kids and the school and community!
Make sure you tell them to "Have a Nice Summer" as you hand the card and flowers to them and make your way onward to school.