Although students worked in groups of 3 or 4, I employed step by step lab instruction. This gave me the opportunity to point out important ideas, ask questions that were critical to understanding the concept and help me focus on what students understood and what they did not. Explicit and detailed instructions for what I expected of them in their lab books and their lab book responses. This also helped students focus on what was important and it also insured that they would think about the concepts behind the activity. Don't assume that students are completing all of the steps or exploring important ideas.
Direction always helps.
Integrating these concepts into other subjects and lessons. Use them again and again. Plus students will be proud of their resourceful ability to recall what they have learned. But I think it is so important and critical to find ways to assure that students learn the idea behind the activity. At first, these ideas were getting lost in the shuffle.