All of the above tips are great, but I'll add my personal method for working on "beefing up" my backgrounds.
The first step is not to shy away from them. When you come to a panel that needs or wants one (note- not every panel necessarily does), diligently try to draw it to the best of your ability (using refs and what not as others mentioned). When you're done, even if it's not great/perfect, call it good and move along.
Then, the next time you come to a panel with a background, do the same thing- but try to make it just a little bit better than the last one. Like look at the previous bg and just try to pick out one thing you'd like to improve upon, be it "i wish the computer panel in the ships dashboard had just a little more detail" or "wow the perspective was really wonky, the doors at the end of the hall look just as wide as the ones in the foreground" and try to fix that thing a little while doing your best on the rest of it too. Granted you might not fully fix the thing you pick (practice takes time,after all xD) but it's still a step in the right direction~ then just rinse and repeat this until the comic's done.
At least for me, focusing on one or two small things to work on each time is easier than having the weight of trying to get it all perfect all the time crushing me. And since comics require so much drawing you'll probably see a lot of improvement relatively fast in my comic there's a scenery that shows up on page 8-9 the first time, and then we see again around page 25. Boyyyyy does the new version of that same location look a lot better with a few more months of practice under my belt xD
Best of luck!