In good weather it is a lovely walk. I was so lucky. Since I am not a fast walker I did it in over the 24 hours but I did bivi for a few hours on the way.
As with any long walk make sure your feet have the best possible. Get properly fitting boots, remember feet swell when you've been on them a few hours. Best socks, so much choice here.
Train for stamina, so try to walk a reasonable distance daily . However be careful not to leave your fitness and health behind by overtraining and damaging feet and tendons etc.
Most important is the mind, you will get cheesed off, tired, sore and you have to learn to get in charge of your mind begging you to pack it in, because it does. Physically you can be ready, but mentally you may not be.
Most important, do it. And if you fail first time , do it again. Treat first time as training.
Remember to do it for fun and enjoyment, that way you take a lot if the pressure off.