However, marketing a thriller is quite easy to get good results as many people enjoy thrillers so it will automatically appeal to them, even if they don't know the sub-genre, as at times they may be marketed in a way to disguise that, for example a trailer which emphases a background relationship to appeal to woman.
The key point to a thriller is suspense, this keeps the audience intrigued, interested and excited.
A good example of a crime thriller is 'Law Abiding Citizen'
This is also a personal favorite of mine, as for a long time you are left without knowing who is doing the killing. There is also a lot of action, and it is always exciting. Which makes it appeal to me more so is the fact it is not frightening. Which supports the mislead fact that thrillers aren't necessarily horrors.
Another sub-genre is psychological and a good example for this is 'Don't Look Now' I personally have never seen this as I also don't like my mind being deceived and having to think about whats going on, as I think these are the sort of films that 'keep you awake at night'. I have however been told about most details, in very long reviews and have been told it's very good. One key feature to this film is that you can spot new things each time you watch it. Little signs that have slyly been included to the Mise en Scene. The color red has great significance, and so you need to look out for that. I think thats why usually psychological thrillers are very successful, because you are constantly thinking and wondering, and always intrigued, looking out for little signs which may mean something.