I'm driving an Automatic 92 accord sedan ex with about 204k on it. I've got the stock rims on it for efficiency. I also have a custom 2.5" cat back exhaust with a thrush muffler on it, and a cold air intake I made for it. Right now my goal is to gain mpgs and still look good doing it. Is there anything else I can do within a normal budget ($750) that will get my mpgs up to the upper 20's instead of the 23.5mpg I am getting now

 

A full tuneup including, Distributor cap, rotor, spark plugs and wires, fuel filter and air filter would help. Could also look into testing your ignition coil.

A lot of times changing your driving habits can contribute to better MPG. The harder you are on the gas and brake peddles, the more fuel you will end up using.

 

That sounds about right for an auto of that year. Mix driving right? I have a 90 Sedan Auto and I get around 22 in the city and 26 on the freeway and only 18 with ac running. I keep my car well maintain. I am not sure which set of wires are better but Sumitomo which is an OEM brand or NGK are better. The resistance is almost twice with the OEM wires compare to the NGKs. Here's my measurements. http://www.cb7tuner.com/vbb/showthread.php?t=193763
There's a study on Honda's tuning and the OEM wires have the best results, even comparing to NGKs. My wires are OEM and it say 1990 on them and still doing well.
There's a seller on Ebay that sell OEM wires for $25 shipped and NGKs cheapest is about $35.

 

Add 3 lbs of air pressure to your tires.