Hi Ian,
I have built most of my hulls with the plank on frame method and I found it really came together after reading Harold Underhill’s books ‘Plank on Frame Models’ Vols 1 and 2- expensive but worth every penny. Also, to use his methods you will need to find a pair of proportional dividers. This makes setting out plank widths along the hull much easier.
I would say, given the cost of stripwood, some means of cutting planks is helpful. I use a two wheel bandsaw and small block plane to clean up saw marks after each cut. Others will have their own methods. A building board is absolutely essential to keep things true.
This is all assuming you are talking about scratch built models and not kits.
Finally, I find the biggest difficulty is that when I have built a hull I find it so satisfying that it can be a good while before I actually finish the model off, wanting instead to start another hull
It’s great fun and you can really say ‘all my own work’ at the end!
Best of luck,
Ian