I tend to try and get the most bang for the volume. Typically I try to pack one full change of clothes with maybe 2 pair of socks. With the exception of one pair of wool socks, everything is thin, light, and packs small. Ultralight Merino Wool long underwear (I'll usually wear this but if i don't, I always pack it), polypro shirt and socks, Nylon windbreaker pants, etc. I also try to pick the sizing such that I could wear these clothes in addition to what I wear out the door and layer it all together if I had to. I buy with this in mind and have a selection of snug, proper fitting, and oversized shirts to choose from.

Ever since I started watching Ray Mears' TV shows his philosophy of 2 sets of clothing only make a ton of sense. He lets whatever happens happen to the set he wears during the day and sleeps in another set which is pretty much exactly the same as what he wears during the day. Then he gets good rest and can dry clothing at night plus has a change if it's a bad idea to wear wet clothing (depending on the conditions of course).

If you put your clothing into a stuff sack, compression bag, etc. Make sure it's big enough to hold the every day clothing you might be wearing when you bug out. Jeans are bulky for example. This is where I love waterproof compression bags. Keeps your other clothes dry and can compress even the most uncooperative items into a manageable size for packing.