I have read many suggestions on how to optimize the burning conditions. What I thought I found worked best was to use Decrypter to copy the DVD onto my HDD, then defragment the drive and reboot. After I then use DVDShrink, if needed, to compress the DVD files on my HDD, then reboot. Finally, I burn using Sonic RecordNow. I use DVDInfoPro to test for Read errors as a measure of the quality of the burn ( I understand that watching the DVD is the best way, but this saves time). However, I am still getting read errors on some DVDs.
I am using a Sony D56A burner with Sony DVD+R (Media ID: Sony). Only other thing I could think of is to slow down the burn speed from 8x...unfortunately, RecordNow doesn't allow for that option, at least my version.