If you would like to support Israel's soldiers directly I recommend these three organizations:
Package from Home delivers cares packages to combat soldiers. This is my favorite. I have packed many care packages for soldiers through this organization. Even more than the food, your personal letters are most appreciated by the soldiers. Since the start of the war this organization has delivered more than 4,300 packages.
IDF Pizza delivers pizza to soldiers. Its promotional video offers a touch of humor to the current situation.
Friends of the Israel Defense Forces is the well-known American charity that raises funds to support Israel's military. Take particular note of the ways to help injured soldiers.
Don't underestimate the good will generated by sending a pizza to tired and hungry soldiers.