I've been camping and hiking for a few years, but only recently had to deal with this issue... I did some car camping with a group, we did a 10 mile dayhike and got soaked during the last 3 hours. It was still raining heavily when we arrived back at the campsite. The only dry place I had to change clothes was in my tent, and I did not want to get my sleeping bag wet, or the other stuff inside of my tent.
Fortunately for me, I was in a 2 person tent and slid my mat and bag over to the far side, so when I came in and sat down it was on the bare tent floor, and not my sleeping bag. As I took my wet clothing off I put it outside under the vestibule. After putting my dry stuff on, I wiped up the water on the floor with a packtowel.
If I had been camping with my wife, we would have had both pads and sleeping bags laid out, and I would have ended up sitting on my sleeping bag and getting it wet.
Any tricks for avoiding this, besides not camping in the rain?