1- Even if you donīt remember any dream, open your dream journal and write down the time you woke up and "blank". you may notice dream memories popping out of nowhere
2- Imagining you are becoming lucid during the day at random times and recalling previous moments during the day (also as part of a reality check) make my dreams more vivid and easier to recall. Might work for you too
3- Eat a banana 3 hours before your usual waking time