We start by separating the pattern pieces from one another, and identifying how they will go together on the body by pinning them into place on a dress form or mannequin.
For those who do not have access to a dress form, try tracing a body onto a large piece of card stock paper.
For this exercise, we used the cover of a binder full of artists' drawing stock. Cut the neck long, and fold it over a hanger. Then pin the pattern pieces into place.
Or, you can purchase from FineFabrics.com a visualization mannequin to which you can apply your flat pattern pieces.
These will not work for fitting, but they are great design tools for beginning or intermediate sewers.