One thing to keep in mind - some people have set up their email programs to direct any incoming suspected spams right into a junk/spam folder.
And once the possible spam email was directed to a junk folder, the sender's email address was automatically added on a blocked list.
I remember a case once a while back someone I knew sent me an annoucement email and it was suspected to be a spam so my program directed it to a junk folder and blocked his email address. So for a while all of his important emails that I was expecting ended up into the junk folder. I didn't know that until I scanned the junk folder and spotted his emails there so I removed his address from the blocked list.
I like what Tess suggested in regards of your email signature. You can also add your website address in your signature as well.