I definitely agree w/ starting off w/ a description of what type of xray you're looking at. After that, there's no real gold standard. Just be consistent and take your time. An easy way to remember the process is:
A_irway (trachea midline, straight, etc)
B_ones (clavicles, ribs, scapula- for fractures, expansion, etc)
C_ardiovascular (heart size, chamber enlargement, obscured borders, arteries)
D_iaphragm (costophrenic angles, tenting/flattening)
E_verything below the diaphragm (gastric bubble, free air, etc)
F_ields (finally, the lung fields themselves, remembering to also check the periphery for pneumo's)
-key is to check symmetry throughout
-If you mention lines (and if they're properly placed)...well, that's just icing on the cake🙂