Apartment Upgrading 101, from my awesome commenters

I've gotten so much great feedback and wonderful suggestions in the comments to last week's post that I can't just leave them languishing away in the comments field-- I think they'd be really helpful to others in my shoes, too. You folks are incredible, thanks so much!

The overarching messages were to make changes based on what I want, and to take things slowly. There were also some terrific tips about what items to target, and ways to change rather than replace what I already have. Here are the highlights, but I encourage you to check out the full comment thread (and add your own comments there or here!)

• gmv: "1) don't let others define your idea of what your material possessions are like and 2) when you get all that adult stuff, the thrill of it wears off really fast... If its furniture you are lacking, can you refurbish something you have with slipcovers or paint? Cheaper than new furniture. If it's artwork you lack, for not very much money you can replace your posters with some more grown-up art. It's amazing how far you can refurbish your look cheaply just by being mindful of the accessories of the room."
• bluntmoney: "It doesn't matter if things don't "match" as long as they go together well (if that makes any sense.) I'd start by deciding what's most important to you, and what overall look you want to have if you decide to change the look of things. And remember to be flexible with buying pieces that will still go in a variety of environments, in case you move."
• English Major: "I totally fantasize about learning to refinish yardsale furniture and making it into something unique and beautiful. I hope to have a whole living space full of projects--things I've invested time and energy (more of that than money) into."
• ISPF: "I just want to warn you that if and when you decide to change your lifestyle, it will hit you like an avalanche. You will want to buy a lot of things at the same time. But if you take it slow, you will have stuff that you will admire and appreciate more and that changes with your changing tastes."
• Madame X: "I think the key thing is not to worry about doing it all at once, as that will break the bank. You can gradually buy nicer things that will last, one at a time. There are also inexpensive ways you can make your space look a bit more grown-up without having to buy all new stuff-- keeping things neat, and maybe framing posters instead of just tacking them up, and some of the ideas that other commenters mentioned. It's also a good idea to keep an eye on Craigslist and similar sources-- I know people who have gotten very nice furniture just because someone was moving or downsizing and needed to get rid of it."
• HC: "If you're going to upgrade, first upgrade the things you must have and can't cover. A well-made couch will elevate the whole room in the way a slipcover rescue version can't. Even a midgrade entertainment center can be a vast improvement on an older, cheaper one. On the flip side, plywood 3-leg side tables can look very nice if covered with a skirt. An older dining table can be dressed up with a nice table cloth. Most other things can be hidden behind screens (desks) or draped with blankets (chairs) to be spiffed up."
• mara: "Posters, Christmas lights, beanbag chairs and sagging couches really scream "dorm room". Even with most of the same furniture and decorations, removing the aforementioned items can completely change the way your apartment looks to visitors. You can buy frames for your favorite posters and pass along the old ones. You can sometimes find quality wall decorations at thrift stores, or mat your own photos/illustrations... If your apartment has enough natural light, plants can give it an organic, homey feel."