The body of the shaft is what slides along the bridge during a shot, and therefore must be straight and free from cracks, dents or nicks. Also notice the diameter of the shaft at this time. Diameters range from 11mm up to 15mm, with custom cues getting even smaller or larger. A 13mm shaft is what most beginners play with because it fits well with most cue balls for straight on and english control, and replacement tips are easy to come by. Also look for shaft flexibility in the body .
All shafts are bendable, but some more than others.
This increased flexibility can allow you more action on shots with english, but may also take accuracy away from your straights and cuts. Meucci shafts are quite flexible, while McDermott and Viking shafts tend to be more stiff, but check each one out individually. The ferrule is the white part at the distal end of the shaft. Having said all that, just know that the ferrule should be seated well against the wood, should not be loose, and should not be cracked. Also notice the seating of the tip .