There are many things that in fact we can do. Some are difficult, some are easy. From enlisting in the IDF, attending rallies and events, making donations to like minded organizations, contacting our elected government officials, reading books and articles, sending emails to those that need to receive them. And more...
I can tell you (you probably are already aware) that thanks to the internet, sending an email is by far the easiest thing to do. And if many of us send emails it can affect change. It's usually a matter of volume. Depending on the issue, it may not take too many emails before a company or organization or person can change their actions. For some issues it may take less and for others it may take far more emails to even get a response. But it's relatively easy to do and more or less cost free (other than your time).
I try to make it a point to send an email approximately 5 times a week. When possible I try to include my contacts in the BCC (blind carbon copy) address part of the email in order that they can read exactly what I had to say to our adversaries or friends. Often I will be nicely surprised by some of these contacts also writing an email to the same person I did about the same issue. We inadvertently compete with each other as to who wrote the better letter. It's inspirational.
All forms of social media are great for getting out your message. Short tweets or longer blogs like this can prove effective. I even learned how to make videos, hopefully effective ones.
I made a satirical video years ago called 'Change the World' which contains subtle support for Israel. You can watch it on Youtube here. Obviously videos take a lot more effort to make than to compose a short email. I often read about an issue that will push me to send an email (either positive or negative). The positive emails are just as important as they help to encourage good behaviour. Sadly I find myself writing mostly negative ones lately.
For example, I recently read about Harvard University's intention to offer a course comparing the notorious 'The Protocols of the Elders of Zion' to the scholarly work Eurabia. You can read about it here.
So I sent the following email to the president of Harvard U:
Dear President Drew Gilpin Faust:
I just learned that Harvard is now offering a course ‘ When the Elders of Zion Relocated to Eurabia: Conspiratorial Racialisation in anti-Semitism and Islamophobia, 11/30/17, the Common Room) that equates the immense scholarship of Bat Ye’or with the notorious Russian forgery The Protocols of the Elders of Zion. Are you in any way, shape or form trying to compare the two?
Bat Ye’or spent years writing several scholarly works that should certainly be studied at school in order to understand how Islam from its beginning was a treacherous, murderous, nonsensical but dangerous ideology and how it has so far successfully undermined democratic states. Look at Europe for one tiny example. Islamophobia is a made up word. There is nothing irrational about fearing Islam. With billions of Muslims in the world today the world has become a dangerous place.
Antisemitism on the other hand is real. I’m sure even you can recall the recent Holocaust where over six million Jews were murdered in history’s most terrible way. No one needs to worry about twelve or so million peaceful and hard working Jews. Between the far right neo-Nazis, the far left violent antifa movement and of course the many antisemitic Muslims taking over the world, it is us, Jews who need to watch our back. Both from people who want to harm us and from institutions like yours who want to whitewash the truth right down to offering courses like yours.
Some sites that promote letter writing, often contain email addresses and even offer sample letters that are meant as a guide for you to put into your own words before sending. One can develop search skills to find the email of the person they wish to send an email to. It's often simple enough. If you want to send an email to the President of the United States, search 'contact president of the United States'. You might have to type your letter in a form presented by the organization's website rather than a free format email.
Some might say that they can't write for beans. Spell and grammar checkers have come a long way and are often automatically at play. Besides it's the content that is far more important than the grammar and spelling. I'd rather have 100 letters with poor spelling and grammar than 1 perfect letter. It's usually about volume. In any case, the more you write, the easier it becomes. I myself am no writer but I manage to crank some out here and there. Writing sharpens the mind and your writing skills will improve over time. It's never been easier to take up the cause.
If computers are not for you, pick up a phone. No phone? Write a letter and stick a stamp on it. In some cases letters in the mail are taken more seriously than emails.
Write from the heart and write often!