Encourage her to keep trying different positions, and move around. The more she tries, the more likely she'll be to fond something that works for her. Encourage her not to tense up during contractions... try & keep her as relaxed as possible. Write down all the ideas you collect/think of, so you have something to refer to if you need it.
Tell her that a big baby doesn't necessarily mean harder labour. My mom explained this to me in an interesting way: Which do you think you could squash better in your fist? A cherry tomato, or a roma tomato? (the answer is a roma, because your muscles experience resistance sooner in their range of motion) The same could be applied to trying to pop a marble, as opposed to a golf ball, out the top of a soapy fist.
I don't know if it's relevant AT ALL to how a uterus works, but I chose to believe it (DH wanted our baby to be 10 pounds... in his family bigger=healthier... DS was 6pounds 12ounces)
A game of cards might be a good thing for keeping her mind off it in early labour, but you might also suggest that she pay particular attention to some of the earlier ones. Since she's sorried about pain, that might be the best time for her to observe what her body is doing exactly, and become more aware of the muscles involved.