I tried rolling the clothes, but what I like even better is packing stuff in zip lock bags. I pack a "set" of clothes (underwear, socks, shorts/slacks, top) in each bag and then sit on it to get the air out. Then when I get dressed in the morning, I just have to grab one bag and a full set of clothes is in there. This works especially well when we're camping and have to go to the bath house for a shower. Grab a bag and off you go! And getting the air out of the bags allows for stuffing more stuff into a bag.
And even better yet - when the Boy Scouts go to summer camp, they use a foot locker for their stuff. If it fits in the foot locker, it goes to camp with him. If it doesn't fit in the foot locker, it stays home. Anyway . . . those pesky boys have a habit of getting very dirty (and smelly) at summer camp. They also just take their dirty clothes and throw them into the foot locker at the end of the day (or the next morning when they're forced to clean their tent). If their clean clothes are packed in zip lock bags, they actually stay clean until they put them on their bodies (for at least 5 minutes).