Woodguy,
I did lots of things to mine. You can start by a good power cord. I cut my cheap cord off and installed an IEC and then put a $50 signal power cord on it. I have tried several up in the two thousand dollar price and they made no difference. The signal cord over the cheap thin stock made a big difference. I also used sil clear on all 7 or so fuses inside.
Using rf on power cord and video cables proved good too.
You sould also look at power conditioning if you don't have it. Each one of these things made a nice difference
I also have a Toshiba 55 inch hd that I was so close to getting rid of a couple years ago cause I just was not happy with the picture. Now you could not get the Tv off my hands even though its an older high def technology it looks great.
Have fun...
