This question is related to How to improve myself as a lecturer?. However, being a PhD student, my main teaching obligation is leading recitations, i.e. sessions for groups of ~20 students that take place each week after a lecture and the content of the lecture should be revised mostly via exercises.
If you do not use the term "recitation session", please see a related question: What is the equivalent of European "seminar" in US universities?
At my university (Charles University, Faculty of Mathematics and Physics, Czech Republic), in the mathematics/theoretical computer science classes, usually you have a 90 minute class where the recitation teacher reminds students of what was said in the lecture, hands out or writes exercises, and then, in shorter blocks, students go through the exercises and one student shows the solutions on a blackboard.
I'm not very fond of this structure and I would like to improve my classes with ideas that I cannot find at my university (where we usually do things the aforementioned way).
Some ideas that I've had in my previous years, which you can judge effectiveness of:
handing out "cheat sheets" containing the entire course notes (with compact proofs) beforehand: usually useful, as lecturers rarely have such compact notes beforehand, but very time consuming.
trying to ask each student how he is faring and offer personal advice: when I was a student, I preferred this model, but it takes a lot of time to go around 20 people and shortly talk to each one; my students (in an exit questionnaire) argued that they want more exercises done per class, so time is of the essence.
allow group work during a class -- this seems natural to me (science is mostly done in groups) but often results in people not being able to perform as well in final exams. Plus I am not yet sure how to allow groupwork so that groups don't delegate the work to the one enthusiastic student in the group.
use text questionnaires through and after a session to find out what students would like; I am very happy with the information in those and will use those in the future but students of one university tend to suggest improvements which they have noticed at the same university (especially where it is expected to go to one university for the 3-year Bc. and 2-year Master's).
filming yourself (as was suggested in the lecturer's question) is definitely a valid option but I feel it won't help me as much with recitations, especially since (I believe) there are not many great recitation sessions publicly available on the internet.