Over 30 and still single, post here.

ElVee

Crazy great advice. Having a plant or fish tank, even in an apartment, transforms it completely. If you have poor lighting or suck with plants, just get a few hearty ones, and splurge on fake ones in the corners and out-of-the-way places where they won't be closely inspected. The fake ones are more believable when next to real ones.

I also love the art advice. You don't need to be an afficionado. If you have money, buy some art from local art students or from a local art fair. It'll be unique, and shows you're generous. Otherwise, find some things that interest you and look up art pieces based on those things on ebay or etsy or something. You can get some really nice looking stuff that to someone who knows the subject, will go crazy over it, but to anyone outside that hobby will just look like a more abstract piece of art. (canvas silhouettes of favorite anime/movie characters, things like that).

And frame your damn posters.