Aside from the sensible advice already given; the key thing for me is to take time.
Most of the disastrous punts you read about seem to have been spurr of the moment things that guys have not had the sense to back out of even when they realise it's going to be bad.
I'm fairly flexible when it comes to physical type. I like the website to be honest and direct...........or at least to appear to be as you can't always tell.
Up to date photos, preferrably with dates. Straightforward blurb without resorting to too much vague waffle about what a lovely girl they are.
The worst disaster I had was with a girl who appeared to comply with all of the above..........except she used the word 'donation' rather than 'fee'
With hindsight, that should have given me a clue as to her honesty........after all it's not a bloody donation is it.
And be careful of Forums. Forums like this keep your feet on the ground but some seem to allow newbies to get drawn into longwinded waffle fests that don't seem to do anything other than provide a marketing opportunity for wordy girls and and showing off for wordy male posters.
Reading a Forum like this is more direct without all the flim flam.