I'd like mine to remember to use parentheses when substituting into an algebraic expression. I stress outlining the problem before replacing the variables with numbers. However, I can't force students to do it. It can be frustrating because if they do outline the problem first, as shown below, they generally solve it correctly.
One little trick I use when working examples for the class is to highlight each space where a number will be substituted. Little things like this can help put the focus where it belongs, and is especially helpful to students who are visual learners.
