The main idea of pretty much any chess opening is to develop pieces as quickly and effectively as possible. Here are some basic principles for white which can be applied to most opening situations in the world.
Knights: Nc3, Nf3 – to double attack the center, to safeguard the king (e-2 square).
Bishops: Bc4, Bf4 – to take a control of a2-g8, a6-h1, c1-h6 and h2-c7 diagonals.
King: Kg1 (after “O-O” castle king side) – to ensure the safety of a king.
Rooks: Rd1, Re1 – to take a control of semi-open files.