For example, if you want to teach your students how to make comparisons or judgements, you can learn a number of different activities that enhance that skill.
Some of the other categories include debate and discussion, group work, and essay skills.
One of my favorites is hexagon learning. Students get hexagons with key information and have to organize it into categories of their own choice.
Tarr provides an example with a case study of Stalin. He put together a list of the factors that led to Stalin's rise and generated 40 hexagons using a digital "hexagon generator" he developed.
You can develop your own hexagons using his generator here at his site, Classroom Tools.
Tarr's "History Teaching Toolkit" is a great resource with a lot of novel ideas.