I usually get messages in dreams and used to wake up remembering them. In the last few years this has changed to lucid ones that are also remembered so I attribute it to the constant energy work, meditation and development. See, these things DO work
As for a dream journal, I find it useful to spend a moment when first waking (when you are not quite awake and not quite asleep) and then asking myself what the dream means, then writing down that guidance. The world f dream and trance is sometimes beyond our ability to consciously understand and so we create metaphors and stories in order to help us to process the information in a useful way. If you just write the content of the dream, it may make no sense at all when you come to review it later. But in that half-waking state, translation becomes easier.