In special education there is a tool called a task analysis. It is a formal approach of identifying the steps taken to demonstrate mastery of a skill. For example, putting on shoes with Velcro straps involves the following steps: get shoes, sit on chair, match shoes with feet (right to right), insert foot into respective shoe etc.
I have applied this approach to general curriculum math topics from counting money to solving using the Quadratic Formula. Below are the iterations of my task analysis for the objective count TENs, a FIVE and ONES (dollar bills) to pay a given price. The first shows a rough draft of notes I took as I actually counted out the money, going through each little step. The second shows the steps written out on a task analysis table I created. The third shows the final, typed version.
The table is used for assessment, collection of data and progress monitoring. The steps that are problematic can be targeted individually, e.g. skip counting by 10s.