Trick for dress shoes that actually works: Go in and buy some that are comfortable to walk around the store 3 full times while wearing heavy gym socks. They should be loose with those on.
That way when you get them home and walk around through the day they will be loose at first, but then your feet swell. When they swell you never get the 'uncomfortable' phase because you bought them that bit too big.
If you don't have really thick gym socks, find a pair that are perfectly comfortable immediately, and buy a half size bigger. If you know they swell alot, buy a full size bigger.
My last job was business attire daily (not even bus casual) and I'm a big clunky skate shoe kind of girl... Until a friend who models taught me this trick I'd end up walking home barefoot and being too sore to even go to the gym after work. Since, I've never had a problem.
Now I"m casual every day and love it!