Place "only" as closely as possible to what needs to be emphasized in your sentence. Be careful! Th placement affects your meaning.

Only Heather hit Ted on the nose.
    Others may have hit Ted elsewhere, but only Heather hit him on the nose.

Ted hit only John on the nose.
    John is the only one he hit on the nose. He could have hit David and Bob in the arm.

My team only threw eight passes.
    That's all they did for the whole game. There was no running or tackling. 

My team threw only eight passes.
    They threw eight passes during the game, but they also kicked a few field goals and cheered.

Only my team threw eight passes.
    The other team and the cheerleaders didn't throw eight passes.