After about three weeks using reality checks during the day and waking up in the middle of the night, I had one about 45 minutes ago. I've had them before, three of them in the late nineties. Since that time, I've tried on numerous occasions to have one again, with no success.
This time, however, I simply doggedly persisted with the reality checks and waking up after 6 hours of sleep. My effort this time was simply more than those times in the past when I had no success. I also put aside as much as possible thoughts like "you're not going to succeed, just like all those times of trying in the past 15 years." I injected thoughts of "you are going to succeed eventually because you are doing all the right things." So, these two factors, dogged persistence and putting aside discouraging thoughts, introducing new positive ones in their place, were the key things, apparently.
I should note two other things that are different this time. I've been taking a one-a-day vitamin every day for the past two weeks. Also, for the past three to four days, I've been taking half-hour naps in the afternoon. I have no idea if these had any bearing on having lucid dream success.
Ok, so I now will continue with all the things I've been doing ...
Wow, excellent! Finally did it! After 15 years!
edit: another thing I need to mention (besides the reality checks and waking up in the middle of the night as my two main practices) is a third standard technique. And, that's the often recommended practice of wishing for and imagining becoming aware and lucid just before I fall asleep when going to bed each night.
Oh, and of course, how could I forget to mention this other standard technique... I've been faithfully recording all dreams in a journal upon awaking.