Every company segments their email marketing lists, at least all those you regard as competitors. The only difference is how well they do it. Most will use the obvious criteria, such as age, gender, location, which means that if you want to gain an advantage you need to do something special.
You will be able to test small groups so risks are low, certainly lower than merely following the crowd. It is impossible to be specific as there are too many variables, but here are some broad suggestions.
The simplest thing to do is to consider the data you have already collected that you aren’t using at the moment. For instance, you will have details of those who signed up following a lead magnet, say an e-book guide to the places to visit in Thailand. If they had already booked a holiday there or did subsequently then you could try sending them a choice of similar books and then, when they pick a particular location, a marketing email for offers on hotels in that area.
What about those who, for instance, abandoned a shopping cart? They might have no other criterion in common so would not have been on the same email marketing list. However, they might be a little nervous of putting their details online. An offer they could not refuse might break through that fear.
What about those who never visit your website? You will have all sorts of goodies and offers but if they don’t look you won’t know what interests them. Have a competition or offer that obliges them to click through to your website. The landing page will have all sorts of options that will help define them.
Another factor not often used to segment email marketing lists is education. Why should you? Well, segmentation is another word for personalisation. You could try using a different vocabulary for those of degree or further education level. No one likes being talked down to.
In summary, try something singular when segmenting your email marketing list. Experiment on a small group first and there will be no harm done if it doesn’t pan out. But it might.