Stop thinking that you "need to remember" let it go and let it happen completely naturally without any insistence on wanting or needing it to happen, because you're kind of creating a loop for yourself that makes it harder to remember the actual dream, or I should say you're introducing resistance to something that is pretty effortless naturally. So just let it go. Usually I only remember pieces of my dreams within seconds of waking up, and if I want to hold onto those pieces then I keep thinking about them, sort of replaying them in my mind until I can write it down.