I noticed that the related fourth grade standard stated, "Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table." Eureka! My fourth graders could do this! All they needed was knowledge of multiplication patterns.
Once the students completed their tables, they could use them to solve all kinds of conversion problems. This was the conceptual link that they needed. In fifth grade, they'll be expected to convert without tables. But they'll be ready!
To make practice more lively, I purchased Customary Measurement Task Cards from ChiliMath. (I use lots of their task cards in my math class and love them!)
Here are some customary conversion tables for you. Just click on any of the photos to download.