I am training nothing. The content of the dream makes me remember it when I woke up. So awesome dreams are memorized better, others are not or fade away in a few days. I dreamt in total 6x about Touhou over a span of one year. I can remember all six of them somehow but that is about it.
Also unnaturally interrupting sleep is not a good idea and should not be done. You don't interrupt your sleep unless you want to cause damage =/
Dreaming occurs between "waking up" and deep sleep. There is a whole bunch of bla bla about dreaming but none of them can be explained normally.
I was talking about training lucid dreaming, not dream recall. That isn't really called 'training'. And waking yourself up is only for say, over summer break if you're in school or on Friday nights/holidays if otherwise, since it disrupts REM sleep. It's a more serious way of lucid dreaming than just 'trying and hoping'. You don't do it when you have school/work the next day or etc., of course.
Recently(Last three days.) I've been remembering the last "30 seconds" of my dreams. Obviously that's not real physical time, but anyways.. I'll remember what just happened pretty well, but like you said, the rest doesn't usually matter so I forget it or don't care to remember if I'm that tired.
I'm proud to say I've never forgotten anything about a Touhou dream I knew I had. It's like.. "Touho- OMG WHAT" And I suddenly remember all of it. :V
Also, gotta quote your "80%".