All of the methods listed are fabulous. Skimming through the chat I agree with a lot of what everyone is saying, and was pleasantly surprised to see someone mention keeping over sexualization out of horror. Anything that distracts from the mood and atmosphere are detrimental. Not to say sex doesn't have a place, and stories are less for having a character now and then that's nicer too look at, but there is so much you can do with your characters and places then have scantily clad sex object laid across mantles for sacrifice or distracting in the background.
While writing my own thrillers I like making sure the actions the characters take are believable. And part of that is having them be regular people (at least at first), with as much knowledge as the reader, and limited resources. Getting in peoples heads, and honing in that hopelessness.. seems rather sadistic when I type it out, but it really makes or breaks the readers suspension of disbelief depending how it's handled.
And with my two cents said, check out Madder Affairs (=
