Not getting much deep/REM sleep, please help

Recently got an Apple Watch (I know it’s not 100% accurate) but according to it I hardly get any restorative sleep. For example, in one night I had 4.5 hours light sleep, 1.5 hours REM sleep, and 40 minutes deep sleep. I’m trying to give myself more of a sleep routine but I’m still waking up and feeling tired/finding it hard to get to sleep. Has anyone got recommendations for things that might help me sleep better? Really would like to get rid of the permanent bags under my eyes (based in UK if that helps). Hope the flair is okay, didn’t know which to choose