I planned a hypnobirth in the water pool with DC1. It all went out of the window after around 15 hours and eventually we ended up with an epidural, diamorphine, failed ventouse and forceps.
With DC2, my only plan was "get baby out alive."
Pure luck meant that she was in a good position, though, and we had a beautiful, peaceful, waterbirth with just a bit of gas and air. Dim lights, soft music, the works. It was an amazing experience and couldn't have been more different to my first birth.
So what have I learned? It's almost all down to luck, and there's only so much you can plan for.
Be prepared for your birth plan to be completely upended, and don't feel like you've done something "wrong" or have "failed" if it does. I felt awful for years after DC1's birth. It was only after DC2 came along that I realised how different two births can be, and how there was nothing I could've done differently first time round.
Oh yeah, and "pain threshold" is mostly bollocks too. Not all births feel the same, and my "pain threshold" currently wasn't any higher on my drug-free birth than during the birth where I needed everything drugs-wise.
With DC2 labour was extremely painful, but manageable with breathing exercises and all the stuff I'd learned in antenatal yoga.
The same techniques did nothing once I was more than a few hours into DC1's labour, not least because he was back to back.
So my tips are to go with the flow, don't put too much pressure on yourself, and remember that a straightforward birth is mostly down to luck and positioning. Hope it goes well.