1, Check for wear, deep grooves show wear.   Signs of bluing usually shows if the cam has over heated. This would happen if the oil fails to get through  for some reason

cam carrier caps check here for sign of wear

What should I look for in the cam carriers?:
 

1. Same with the carrier caps, but also you should check the oil way, make it is not blocked.

check here and the oil way

What should I look for in the Camshaft
 

1, Check for scratches on these two parts of the camshaft

on the left, where the runs through the carrier  and on the right, the cam itself

Here you can see a cam lobe which has not had enough lubrication.  The discoleration has been caused by heat. Fortunatly the lobe and rockers are not damaged as we caught the fault early enough.  (photo from Yoshimura/Suzuki GSXR 750)

2,  check the size on the cam lobe, with a vernier gauge and using your manual, see of it is within the tolerance stated

What should I look for on the cam Sprocket 
(if you have chain type cam drive)