Yes, this is an email marketing blog, not about SEO or SEM. But everything about online marketing is related, and using the correct keywords in your mailings isn’t an exception.
When Internet users are searching for a product or service normally use a small range of colloquial keywords. For example, may be your target uses “online courses” instead of “e-learning”, do you know what I mean?
So, if you are choose right keywords that fit better into your target needs and use a short and personalized mail subject, you will see how your CTR grows (of course, also the sales will do).
Eg: “John , try our new online courses.”
But be careful and don’t be too sensationalist, because your email can be flagged as spam by spam filters.
Eg (not to do): “A great new offer!!! save money by trying our new online courses, for free!!!”
(Yes, I’m going just a little bit over the top)
Choosing the right keywords
There are many sources where you can get this data from. The most important are your website statistics, a system such as Google Analytics will reveal which are the keywords most used by your visitors, and which of them convert more sales.
After this, you should use a keyword tool (or several) to confirm that your site is oriented to the correct keywords, or find similar keywords and identify search trends that could help you to improve your business.
These free keyword tools are my favorites:
Good luck!