First off, some standalone players tend to be a little picky about the media you feed them.

I've actually found that the cheaper players seem more widely accepting of a variety of blank media.

Booktyping +R format discs to DVD-ROM can certainly help some of the more picky players accept the media.

The brand or dye of the blank media is also a bigger factor than most newbies tend to believe. These guys have already posted about that, and they're right. There is no substitute for good quality blank media.