Teachworks already has a simple way of improving deliverability in emails (learn more: Improving Email Deliverability). You can enhance deliverability even more by enabling DKIM.
How it works:
1. Go to Account & Settings > Account Settings > Company Information.
2. If you haven't already, verify your email address by following these steps: Improving Email Deliverability.
3. Your email field will look something like this. Click the "Add DKIM to DNS" link.
4. Click the blue "Add DKIM to DNS" button
5. If you have access to your DNS records, add the DKIM and Return-Path DNS records to verify your domain and ensure effective delivery (alternatively you can provide your Web host, DNS provider or website developer with this information). If you're unfamiliar with DNS, contact your web host for more information.
6. Once the records have been added, click the "Verify" buttons in Teachworks to complete the setup.
7. If everything has been set up correctly, and the changes have been propagated, it will show as verified. If the message says it's still not verified, you may need to wait a while and try again.