Stuck For Lifetime!

There are countless reasons I'm afraid. But the main one is probably that you're not thinking about the way chess works correctly (has more to do with intuitive processes than you realize). I bet you'll be surprised by just how many different articles have been written by Aiden Rayner (among others) about how our brains don't work as well/predictably as we think they do in processing complex systems (such as chess).

And what to do to improve? Ah, I hope going from 700 to 1000 can't be impossible? But so far, it appears to be so.