I tried pot once. It made me want to rape and kill.
For a cheap tweak, get two unfinished Maple Shade 2" thick unfinished Maple platforms. Spike the platforms to the floor through the carpet. Then spike your speakers to the platforms. This was a terrific tweak in my system.
Replace the speaker's binding posts with Cardas copper binding posts.
Take the cover off of your amp, preamp and phono stage.
Keep in mind that the system is full of mico-vibrations. The more you do to damp them (within reason) the more clarity you'll get. Ultimately, the only thing we want vibrating is the stylus in the groove. So, if you use tube, get tube dampeners.
For CD's ... go to RAdioShack and buy a VCR tape eraser and use that to demag your CDs before playing them. Cheap and effective.
Buy a new turntable belt from Originlive. www.originlive.com. Amazing results from this ... and mine was $44.00 direct from the U.K.
Before a listening session, turn off all electrical devises in the home if possible. Don't forget to plug the refrigerator and freezer back in when you're done.
Clean all contacts with CAIG (red) contact cleaner, including the speaker spades. Finish up with CAIG's ProGold contact enhancer. Don't forget the tube pins. Oh, and the cartridge male leads as well.
Order the best tubes you can get. Here's the site I use: www.upscaleaudio.com