What do you mean? From what book? Usually a general CP text is fine. Every micro lab has a bunch of textbooks that are worthwhile references.
Do you mean physically? Some people spend time in the micro lab. Others spend time elsewhere reading. Others spend time "in the library" which means doing something other than microbiology.
Try looking at Diagnostic Bacteriology by Bartelt. Less than $40 on Amazon.com. I wish I had found this book while I was still taking micro during AP/CP residency. I studied this for boards, and it was an invaluable resource.