I've had a fairly even split of DILDs and WILDs, but I've noticed a big difference in how they manifest. The DILDs seem fairly random: a few weeks of MILD (using the exercises from LaBerge's ETWOLD) got me started a few years ago, but since then I haven't been able to trace any correlation with how much I practice MILD or ADA or other daytime techniques and how often I experience DILDs. In fact, the only correlation I've been able to observe at all is that random DILDs seem (perversely) much more likely when I'm busiest in waking life. Just when my schedule clears up a bit and I'm like, "Yay, more time to dream!" they become irritatingly elusive.

WILDs are a little more reliable in that you can induce them directly -- with good technique, strong will, practice, and luck (or whatever you want to call the wildcard factor, "luck" is as good a term as any). If you're not having much luck with DILDs to start with, why not spend some time trying to learn how to WILD?