Difficulty: Moderately Challenging
Step1
If you are not even a med student, make friends with faculty at your local university. Cadaver labs are sometimes under-booked, and friendly professors may be willing to accept non-students, or simply take you in during off-hours.
Step2
Be respectful. These people donated their bodies for your edification, not to be the butt of jokes. If you need to cover the face to relax, you can do so. A simple cloth might work best, as the garbage bag or hood used by many labs can be slightly unsettling.
Step3
Start slow. When making your first incision, you'll be surprised by the resiliency of the skin. It might be to easiest, at first, to try separating the subcutaneous fat from the skin.
Step4
Open the chest cavity, removing the breast bone in the process. This will give you ready access to the rest of the interior. You will also have to make your way through the thick layer of fat, the omentum, that enwraps the innards.
Step5
Scrutinize each organ one by one, removing them from the cavity if necessary. If multiple bodies are at your disposal, try weighing against each other the lungs of a smoker verses a non-smoker.
Step6
When complete, replace all the organs in the proper place. Clean your workspace.