I think both of Minimans' pics are excellent, but I especially like the second shot from under the station canopy - wonderfully atmospheric and gives the feel of a grubby, run down small station. Even the grass and other foliage in both pics doesn't look greatly out of scale, which is so often the giveaway with garden photos.
Your pics are great too, Roly, I love the second one; as others have said, my best suggestion would be to keep as much "real world" full size stuff out of the background of the shot as possible, and watch for extraneous things like that broom! If you're REALLY striving for realism (to the extent of convincing the viewer, at least at first glance, that they are looking at a 1:1 scale train) then it might be best to avoid taking the shot on stretches of line where things like LGB point motors are visible; on the other hand if you just want the pics to be a "realistic-looking garden model railway" that really doesn't matter.
My yardstick (do the Europeans have a metrestick...?) for "realism" in photos would be whether the casual viewer is fooled, even for a few seconds, into thinking that they are looking at the "real thing". To me it doesn't matter if a few more moments of careful study will prove that they aren't, it's that first impression that matters. Model Railroader (the US indoor-scales mag) has a wonderful section in the back of each issue of "trackside photos" - and even though I KNOW they are all models, quite often I have to look at some of them for several minutes before I can spot anything that convinces me 100% that I'm not viewing a 1:1 scene!
Jon.