I just finished off a camping trip yesterday and I almost had a heart attack. We got one of those double heighth queen air matresses from Wally World and not only could I easily get all the air out, I folded and rolled it up and it went back in the factory bag.
For my tents I usually roll them up with the poles and ground clothes and flys together, so I get a new bag that fits easily. My backpacking tents always (finally) got stuffed in the factory bags, but you need to make sure you get the far side in first and the OPEN door in last to let the trapped air out.
I keep my various mummy bags in big bags all fluffed out for storage so when I actually stuff them in a sack I use after market compression straps. You aren't going to get a nicely fluffed out sleeping bag in a small sack without too much work. So you use the compression sack and then go around a few times pulling it down to size with the compression straps.