Make your sleeping environment as dark and quiet as you possibly can. If you have tinnitus or are troubled by background noise, look into getting a white noise generator. I was given this one on the NHS by my hearing therapist, and it was very useful when I was living in a noisy place and with a landlord who liked to play loud music at interesting hours, not to mention helpful when I was going through a spell of bad tinnitus. It makes a variety of sounds as well as white noise, which is useful as it’s normal to find that some or most of the sounds annoy you, while there may be only one that you find soothing. I personally liked the rain one. It can also be plugged into a special pillow if you have a partner.
The rule for how dark your bedroom should be at night is that you should not be able to see your hand in front of your face. I used to sleep with an eye mask on, but while my one was also good for dry eyes it was not a particularly friendly thing if you have a partner (he used to call me Bug Lady ,and would yelp if the bulbous shape of the eye mask hit him during sleepy cuddles), plus I decided that I wanted to try dawn simulation again. There is some research suggesting that light is taken in by the skin as well as by the eyes, so some people think an eye mask won’t do if the room isn’t dark enough. There are several views on the subject, though, and personally I wouldn’t worry about it. If an eye mask suits you and doesn’t fall off during the night, then go for it, it’s a nice easy solution.
Once I stopped using the eye mask, I had to go to quite a lot of effort and a certain amount of expense to get the room as dark as possible. There’s a borrowed light above the bedroom door which lets in light from the hall (which itself lets in light from the stairwell through a borrowed light above the front door), and I taped a piece of blackout fabric onto that shortly after I originally moved in years ago. The curtains are beige and glow nicely when the light comes through, even when I have my not-terribly-efficient blackout blind down, so I bought blackout curtain linings and they improved matters quite a lot. Lots of light still came in around the sides and top, so I bought self-adhesive velcro and stuck one side to the window surround and stapled the other side to the blackout linings, thus blocking off the light at the sides. I did spend a while still being woken by the small amount of dawn light coming over the top of the curtain rail, but this settled after a while. I don’t know whether it was an adjustment period or whether it was because winter set in and it was still dark when my alarm went off. I found that it took me a while to get used to not having the eye mask on any more, for some reason, but I now sleep absolutely fine without it.
All of this would have been considerably simpler if I did not have 10′ high ceilings, which meant that my original curtains had to be custom-made, the only affordable blackout blind available was a cheap and nasty thing from Ikea which was still a few inches too short, and I had to buy extra pieces of blackout fabric and sew extensions onto the blackout curtain linings. If I ever have to start over with a similar type of flat, I think I’ll look into the cost of having shutters made instead.