Just wanted to add that you might still do some cardio as warm up before lifting. Cardio is important in a sense, but you don't need to be 1/2 hour or 1 whole hour in the treadmill or the stationary bike.
(Which is a blessing, since once you realize you're moving but going nowhere, cardio becomes utterly boring and senseless, not even watching a tv screen while doing it can ease your mind about it)