You might think, since I'm a mathy, nerdy type, that I'm as cool as a cucumber when making soap, but I'm not. Especially in the first year, I often had to take a break between getting everything ready and actually making the soap. I was so flustered and flummoxed with all the measuring and melting and stirring, that I needed a moment to chill before the real fun started.
Some things I do that help me to keep a sharp mental focus --
I make a recipe checklist with boxes for entering weights for measured ingredients. If there's no weight to enter, I put a tick mark at each step as I finish it.
I put ingredients on the counter in the same order as they are listed in the recipe.
Once an ingredient has been used, it gets put out of easy reach on a separate counter so I'm not tempted to grab it absentmindedly.
If possible, I put everything into the soap pot up front, rather than hold anything back to add later on. Some fragrances and some designs don't allow that, but many do.