Small groups can present articles, teach techniques to one another, present different sides of a debate. Have students peer-edit one another's work. Require small-group reports on primary articles. Small groups should progress reports and oral reports on their research. Classmates can rate and give feedback on reports.
Poster sessions can be very effective.
Peer-editing helps students learn to express themselves. If you are trying a new lab technique, you'll run pilot experiments to see how it works. Classroom Assessment Techniques are ways of finding out how your course is working and how the students are doing. In the middle of a discussion or lecture, ask students to take a piece of paper and write down their understanding of the most important idea being discussed. Let the students know you will collect these, with names, to let you know how well they are understanding the concepts.