I've done a few 'oreflight / new plane' checks on a few planes.. here's what I usually look for:

(Sad, but I have had to tell some newbies taht the plane ain't gonna fly today..)

-Check that all servos have their screws, and that they are secured properly to the servo tray / rails
-Flex control surfaces to see if there is some slop. (Found one plane, that used undersized wire to make the control rod connections, and teh surfaces easily moved, while not moving the servo arm.)
-Check that antenna is run in a proper fashion, through the airframe (that it isn't coiled up..)
-Check fuel tank, and fuel lines if accessable.
-check engine, and that its mounted correctly / securely
-check prop (dings and cracks mainly..)
-look over wings, (ailerons, servo, wing tips glued, ARF wings actually glued together, or that the secureing device is installed, and secure)
-Pull the control surfaces, to ensure they are glued in place! how many times I've found a rudder not glued!
-Check that all control surfaces move teh speicifed, amount, and don't bind (had one plane, where the aileron LE wasen't beveled, and did bind when defelted..)
-check balance
-Check that the radio does what it's supposed to do; move teh correct surface the right amount, and in the right direction..
-Check teh wheels, that they rool, and point true..
-Have the pilot assemble the plane, and do a range check
-Start it up, and give it teh 'noze up test'
-pass it off ot teh instructor.