I had a basic bike fit done at On Yer Bike in Burnley a couple of weeks ago. They first measured me, using a laser on several points of my body, then did the same with my bike. They then plumbed my make and model of bike into their computer and it told them what distance from eachother various points on the bike needed to be and they adjusted it to suit.
The process took around an hour, the net result was that my saddle was lowered a tiny fraction and the stem was flipped so it rises rather than sits flat (although they said I could do with one with a 10 degree rise rather than the 7 I have now, but remaining at 110mm). I fully appreciate that these things can go a lot more in depth, but what I do know is that my bike is more comfortable and I now find climbing easier. For £25, I’m more than happy.