I'm not an artistic person by nature - I'm a hardcore scientist is what I am and always will be. I've no issues with the technical stuff and can calculate the angles of view or pixel pitches etc till I'm blue in the face.
So I find composition is the "hard" bit of photography.
Some of it's straight forwards (like the rule of thirds etc) but I am currently reading
this book which is all about how we look at and read photos. It's full of useful information and has taught me
loads about composition.