A/B testing is used to determine which of the two campaign options provide the best results as far as opening emails or getting a response goes.
During the test, you pick a small number of recipients and create two email versions—version A and version B. Half of the recipients receive version A, and the other half—version B.
Usually, the winner gets decided by how many responses or opens an email gets. After knowing which email copy of the two is more effective, you can send it to the rest of the recipients.
Take advantage of A/B testing for different call-to-action combinations, subject lines, personalizations, body texts, headlines, and other cold email elements.
To make your A/B testing more effective, focus on testing one thing at a time. Moreover, always test both versions simultaneously to avoid skewed results due to time-based factors. It is also recommended to have as large a sample size as you can. Finally, stick to numbers instead of your gut feeling and use available testing tools for efficiency.