@Trinity369 For me, fantasies are the core. What do you imagine and how does it make you feel.
There is a * there. I know first hand that the mind can have a lot of different categories. IE You may see/imagine an image of a larger woman and either be turned on by her or the particular way her belly folds. The mind has each abstract idea as a separate thing and any of them can be your thing. As such, I recommend imagining a variety of things.
I like the idea of a couple but get grossed out if I place myself in the role of one of them.
Also, if you find you are only into something very niche, such as my enjoyment of the plot where a supervillain changes society by introducing something that changes the way people think, do look it up as you'd be surprise how many more people like either the same thing or something similar.