Use better cable. That's a big help sometimes. (Especially if you made a coaxal cable and didn't buy it. They're hard to make!)
Run the input through a VCR first. The VCR amplifies the signal before it gets to the TV, so you get a stronger signal. I can pull in Comcast Sports net only if I go through the VCR. (Comcast in Fort Wayne has really poor cable quality.)
You will probably see some fuzzyness. The reason is NTSC (standard TV) resolution is 388x240, while standard computer resolution is 800x600. Many monitors run at 1024x768, so what probably happens is digital enlargement. Digital enlargement tends to be grainy.
