In the diagram, all the pieces:
- are attacking the centre squares
- have moved only once.
This is an ideal position for White, achieved after ten moves.
In a real game, you're unlikely to get the chance to place all your pieces this way: it depends on how your opponent moves. But try and put as many pieces as you can in their ideal positions.
Usually, you should move each piece only once in the opening.
This is because, if you waste time moving it again, you delay bringing more of your soldiers out on to the battle-field. They are there, behind your wall of pawns, eagerly waiting to pounce into action in the middle of the battle-field.
Also, by not moving out your back pieces, you may lose the chance to control useful squares.