Hmm...maybe it's all down to a case of observation of your surroundings in waking life.

Do you tend to be a great observer of things, like, for example, the way bricks make up a house, or the shape of a leaf on a particular tree or plant?

I always have been, so therefore, i usually realise i'm dreaming when things look 'too' real, if you know what i mean.
Maybe you could try that...really study the world around you as you are going about your daily life...ask yourself if you could possibly be dreaming at this moment, and give good solid reasons to prove yourself awake.

That might improve your dream visuals...
someone also said dream spinning can help, but i've never found it works.
Or you could try rubbing your hands together, that's supposed to increase realism...it's worked for me a couple of times.

Hope this helps!