I literally picked a few letters I wanted to eliminate with my third guess and couldn't find a word that existed using the first 3 letters and eventually came upon the answer as one of the only ones.
Just reinforces my view that after a very basic level, its largely luck. I usually get them in 4. Occasionally 3 and occasionally 5.
I think there is some luck to it, but it's largely strategy. I've an unbroken run, though I've had two very difficult fives/sixes which were only successful because of careful logical deduction of what the word could be given the way the English language works.
An example:
https://forums.overclockers.co.uk/posts/35438010/
Sorry, can't remember the words but the process here was great.