Go to any bookstore and browse through the science fiction and fantasy section. Look at the covers. Within any genre, there is a large range of readers.
Some readers are fairly new to reading or fairly new to the genre.
They may not have well defined tastes and may not really know what they are looking for. Others may have been reading for a long time and may know exactly what they want. And, of course, there are lots of other factors - age, gender, education, and personal taste. The ideal reader for your book is someone who likes that type of book and writing style. He or she will be able to identify with your characters and their problems.