To differentiate between sp3, sp2, and sp hybrid orbitals, examine the saturation of the molecule. If all bonds are single, the hybridization is sp3; if there is one double bond, it is sp2; and if there is a triple bond, it is sp. The first step is to draw the Lewis structure of the molecule to visualize the bonding. For carbon atoms, if there are no unsaturated bonds, they will be sp3 hybridized. Understanding these principles allows for accurate identification of hybridization in molecules like C2H2 and C2H4.