It sounds like you're starting to take your photographs quite seriously! As you know I'm not a photographer, but I do know of some books that might be a useful as a next step.
For technical support and advice
Freeman, The Photographer's Eye
might be useful.
For a start around thinking about the image, then I'd recommend Berger's Ways of Seeing
and for something more image-specific, perhaps Sontag, On Photography
You might (or might not) want to get a sense of what contemporary trends are in photography in your area - if you do, your Arts Council funded regional network is a good place to look - I think you're in the Southwest - a quick filter of 'photography' shares some interesting work.
And I'd recommend Colossal
(Julie often posts links to interesting things from Colossal on here, too) and It's Nice That
to get an idea of wider contemporary trends in the visual arts?
I hope these help,
(Apologies, as these are Amazon links. I'm not keen on Amazon, but you can also buy these second-hand and they're only a few pounds on kindle, if you find e-readers useful)