1) Pray - every prayer counts.
2) Take upon yourself to learn more Torah and perform more mitzvot.
3) Donate blood. The soldiers and the nation need it. I gave blood today.
4) Be an internet warrior. Counter the anti-Israel propganda spread by Arabs and other Jew-haters on the internet. Here are some sites that can help you:
And of course there are many good blogs. Two which I find especially useful are The Elder of Zion and Israellycool.