My students have gone through all the typical linear stuff, but they're still weak on creating equations of lines from two points or in describing what certain aspects of the equation mean when representing a situation. To help give some motivation to practice the skill, I have a bunch of experiments in which we gather data, create lines of best-fit, and create equations to model the data. The experiments aren't amazing or anything but they beat a worksheet hands down any day.
If I'm honest, it takes more work than I'd like to admit to pull of a good experiment but the increase in student engagement and the rapport it builds with students is amazing. And, it's fun. Fun matters. A lot.