How to improve myself as a recitation (discussion,lab,tutorial) teacher?
I've taught Biology discussion sections, and trained graduate students to teach. I'm a biology education researcher, so I am familiar with studies that measure student learning in different environments. I'd summarize good teaching as follows:


Find the student misconceptions.
If you are good at your subject, you likely have not struggled to learn it. Your biggest mystery is what do students not understand. Unfortunately, students don't have the meta-awareness to tell you, so you'll need to figure the misconceptions out together, at least for the first run-through of the course.
Show students their misconceptions.
Because students don't know what they don't know, they often feel like they understand material that they actually do not. When you show them they don't understand, they are more eager to fix the problem.
Give students an opportunity to learn.
Your class activities will indeed include a lot of group work, because discussing a problem, asking questions and answering them keeps everyone improving right at the sticky points. The big secret to group work so that everyone stays busy? Groups must be only 2 or 3 students. And you'll be walking around and asking the quiet students what they have figured out, so there is no slacking.


Here is an example of how to make this work. It's copied from an earlier answer of mine.


Look over the problem set the night before, and determine the easy ones from the hard ones. 
When students arrive, tell them to start work on a difficult problem. Plan on giving them 5-10 minutes -- whatever they need until many of them slow down. Walk around as they work and just see how they choose to work. 
After several are stuck, have them get into groups of three and compare their techniques and what they found difficult. 


(note: students hate group work because it is more painful than just listening. Most classes will try not getting into groups, or not really talking, just to see if they can get out of it. A cheerful forcefulness works well on American students)


Walk around again and ask questions like, "Tell me how far you are. Can you show me a part that is difficult? Can you get out your lecture notes and find the section relevant to this problem?" 
Usually at this point you will see a sticky point that more than one student is wrestling with. Now is a great time to pull everyone's attention back to the front of the room and you can work through that problem (or one similar) and answer questions for 5-10 minutes. 
Have students return to the problem and complete it. Then they can do a similar problem on their own to reinforce.  
Move on to the next topic and assign a new, difficult problem.


As you can see, this process shows both you and the students what they don't understand, and provides space and motivation to fix the problem. Because you're visiting the groups, they must produce.  

Things I wouldn't recommend for a recitation:


Making course notes or a study guide. Students should be making their own.
More lecturing
Questionnaires are fine, but again, students don't know what they don't know


We've actually posted an example of discussion work for biology here: http://vimeo.com/33801546