How do I find the right lab?

The short answer: With a lot of effort, a probably some trial and error.
The long answer: There are dozens of laboratories at Yale that host undergraduate research projects every year, in addition to the hundreds around the United States and abroad that offer summer internships and fellowships. Finding a good lab is a balance between interesting research and a good working environment. The importance of this second part should not be undervalued, as a positive work situation often leads to better research. In addition to these two factors, you may want to check:

• Size:The lab size suits you (too small and there may not be enough graduate students to help you, too large and you may feel lost in the shuffle).
• Activity:The lab is currently in a state of good productivity and research (a good measure of this may be to check for recent publications from the lab, although that is certainly not the sole measure of production).
• Stability:Make sure you take into account whether your research advisor is a full Professor, Assistant or Associate Professor, Visiting Professor, Lecturer, or Emeritus. Is your professor just getting started? Planning on leaving or retiring soon? Unsure how long he will be at Yale?
• Grad Students:Be sure to meet the graduate students in the lab, since these are the people you will be most likely to work with on a daily basis.
• Undergrads:Check if other undergraduates have worked in the lab, and if so, what their experience was.
• Your Project:Make sure the lab is looking to help you develop your research. Working on an experiment tangent to or in conjunction with another project in the lab is a great way to start out, but make sure that you are getting a feel for the creative process, not simply doing someone else’s work. Think about what the project has the potential to teach you, and to what extent it will develop or tell a story rather than having you do the same thing again and again and again (which is a big part of science, don’t get me wrong - but in the good projects, there’s at least the prospect of moving on to Thing B after Thing A finally works).
• Don’t forget about the Medical School, School of Forestry and Evironmental Studies, School of Public Health, Peabody Museum, Yale Institute for Biospheric Studies, and other departments. All of these have active research labs that hire undergraduates.