This is the question I hear all the time. What one thing I can change? Usually the answer I give is not what people want to hear and will not do.
If you truly want to sleep better tonight you need to shut down the electronics. Not just right before you go to bed but at least 40 minutes before bed time. This includes the phone, tablet and the television.
In order for our brain to make Melatonin we need exposure to darkness.
That does not mean turning on a filter to a phone or tablet. It means we need to turn down the lights and read a book or do another relaxing activity. Do some stretching or deep breathing exercises to help wind down.
I would also suggest that you put the cell phone on the opposite side of the room face down. I would also use the do not disturb feature. This will not block calls from people on your favorite list but it will block the sound of texts, IMs and spam calls. The benefit to having the alarm go off across the room is that you have to get up to turn it off which will help you to start the day.
No one needs the television on to sleep. Television prevents you from sleeping and in fact will wake you up during the night. Advertisers take advantage of the fact that sleep deprivation reduces inhibition to sell you products. The flashing lights at 3am are designed to wake you up. It is not just about sound but it is about light.
If you truly want to get a good night sleep and fall asleep easily then take the time to prepare for bed and embrace the dark.