Most mornings the dream is gone before you sit up. In a YouGov poll of 1,000 U.S. adults in October 2022, 29% said they rarely or never remember their dreams, 44% said they sometimes do, and 25% said they usually or always do. Taylor Orth, "What do Americans dream about?" (YouGov, 20 December 2022)
The minute after you wake is when a fragment is still there.
Stay still for a minute
Keep your eyes closed if you can. Leave the phone where it is, and leave the light off. Notice the feeling first. Then notice a person, a place, or a color, if one is still around. "Cold stairs" or "someone from an old job" is worth writing down.
Getting up or looking at a screen hurries the dream away, so write the note first.
Write it before you get up
Put a pen and paper where your hand already is. A notebook in another room costs you the dream on the way to it. A phone is fine if the note is the first thing you type.
Write the date, including on a morning when nothing comes. Then the first feeling, anyone who was there, any place you can name, any color, and the fragments, in the order they show up. Fragments are enough. Three words count as a sentence.
If the page is blank, write "nothing this time" under the date. Leave it there for the next morning.
Print the morning page. It is one sheet, for A4 or Letter, with lines for the date, the first feeling, people, places, colors, and fragments. It is free, and it does not ask for your email. Print a few copies and keep them by the bed.
The night before
As you turn the light out, you can decide that you want to remember. Once is enough: "I'll notice the dream when I wake."
Elizaveta Solomonova and Michelle Carr write about this in "The role of attention and intention in dreams," a chapter in Access and Mediation (De Gruyter). They describe writing dreams down, and deciding beforehand that you want them, as ways of paying attention so more of the dream comes back. Read the chapter.
Sleep
A similar bedtime and a dark, quiet room help. Leave the phone face down, or in another room if you can still hear an alarm.
A note on your phone
Paper is enough. If you want the dreams somewhere you can search later, Dreamala is a dream journal, free on iPhone and Android. You write the dream down first. It asks a few questions that help you recall details, and then it develops a photograph of the scene. The photograph is an interpretation of what you wrote.
The morning page does not need the app. There is also a longer note on keeping a dream journal on your phone.