Here's something I've found to be highly effective:
Instead of having students decline 1st declension, then second declension, then third declesion, etc, try having them go across the chart, filling in nominative, then genitive, then dative, then accusative, etc.
So, instead of:
Have them write:
am um em um em
This way, students start seeing what each case looks like. It's a good way to mix up an otherwise standard exercise, and it forces students to organize their thinking in different ways, always a good thing.