Planning an experiment is like planning a reconstruction - it's really, really easy to forget something. Where something can be a minor detail or, if one is a bit unlucky, something that seems like a minor detail at first but turns out to be rather crucial.
I've also found, in the number of experiments that I've either run, or co-run, or been somehow a part of, that it is quite easy to forget that one had planned to make photos at a specific point, or that something has to be changed and this all results in a number of hectic notes that are scribbled somewhere.
Part of that is just business as usual. Not every experiment runs as planned, and sometimes adjustments have to be made on the fly. But I found that good prep is really helpful... and that having a good template for the planning makes the good prep easier.
I've recently updated the experiment planning template on the Textile Forum website, and if you're interested, you can find it here. In case you are using it, please let me know if you have any comments or feedback - I'm always happy to hear about this!