The Standard Tee is a fitted ringspun shirt. It's soft, smooth, and has a more fashionable fit than a unisex tee. Be aware, however, that they aren't preshrunk, so they may shrink slightly.
Chest:
Measure under arms around the fullest part of the chest. Be sure to keep tape level across back and comfortably loose.
Waist:
Measure around natural waist with a measuring tape.