How would I decorate a bedroom like it's the year 1980?

The title of this thread and your question are in conflict.

Why not tell us how it currently is and what you mean by 1980s bedroom decoration.

"Grown up" now why the hell would you ever want that title? It just makes you age faster. Never "grow up" its the only thing keeping you from dying.

Consider Pantone's Colors of the Year from 1978 - 1982. Basically, colors went from earth tones to much more in the way of saturated tones. Watch some music videos that were popular in and around 1980 (I am suggesting a few years before and after because the 'look' of a particular year is often a combination of a few years before and a look ahead to a year or two afterwards.

Look here for the songs that were heard a lot during 1980:
https://en.wikipedia.org/wiki/Billboard_Year-End_Hot_100_singles_of_1980

However, I don't recall hearing all of these on the same stations. You would not, for example, hear Barry Manilow and Pete Townshend on the same station, or Bette Midler and Anne Murray.

1979 is more dominated by disco:
https://en.wikipedia.org/wiki/Billboard_Year-End_Hot_100_singles_of_1979

1981 is starting to be infiltrated by new wave (mainly The Police):
https://en.wikipedia.org/wiki/Billboard_Year-End_Hot_100_singles_of_1981

1982 pulls the more popular tunes away from schmaltz (The Human League and Billy Idol are on the list), but it never gets to punk: https://en.wikipedia.org/wiki/Billboard_Year-End_Hot_100_singles_of_1982

Of course these lists of the most popular songs don't tell you the whole story. I can assure you that when Air Supply came on the radio, I turned it off, as did a lot of other people. Actually, the week to week list is a bit better: http://www.billboard.com/archive/charts/1980/hot-100

If you want to listen to some music and maybe get some ideas from how videos were styled (but understand directors would go over the top a lot because music videos were really popular and they were doing anything to start out, here's Blondie's Rapture from 1981:


Not great but the fashions might give you some ideas. Try the VH-1 show, "I Love the Eighties" and see if you get ideas there.

Try going to a bookstore that sells home design magazines - if there is one in your area. If not, look them up online.

1980? just another year, 4 years after we bought the house; we had already repainted, etc.