One of the first things we did was to get a scale drawing done of the flat. I find it alot easier to see things from this perspective, without standing in a floorless grease pit. All emotion removed, literally leaving it to the maths. I've always seen things as black and white (possibly something to do with being a Geordie?) and when you're standing in a room with the windows hanging off and damp patches I find it hard to take myself out of that and imagine anything other than what's in front of me.
With a floor plan, a blank canvas, it all comes to life and the possibilities (budget permitting) are endless. You can also easily see if things will fit where you want them to (like a 1700 bath, which we realised would NOT fit in the space we imagined) What looked like a large space, was purely a trick of the eye, and we in fact, ended up going with as 1500 bath!