Your timing seems right, so it is probably your mental state. You need to barely wake up and still be on the verge of a dream. Do you fall back to sleep? You must fall back into sleep AND stay aware at the same time. It still takes skills used in WILD and has the disadvantage of a high failure rate due to you drifting into an unaware state easily. Its big advantage is not having to wait for REM.
Learn about the mental state and tricks in WILD and use them in DEILD.