fig. 1-1 Too much crap...for the record...
While we're on the topic of furniture, let's talk about your bookshelf...
Don't have a bookshelf? Go to Ikea at least and get a bookshelf. I'll wait.
Okay, you have a bookshelf. What should go on your bookshelf? Books, yes. But the selection of books is important. The recommendation is obviously for starter, the books you read. On top of the books you actually read, toss in some books you don't read. Why? Cause it puts out a good vibe.
If you haven't guessed, we're planning for women to come over, because one of the first things people will usually inspect is the bookshelf.
Putting books up, say philosophy books, science books, or any other real deep literature will only make you seem more worldly. The only caveat, is you need to know enough about the book to talk intelligently about it, not just know what it says on the back cover. Right now, I have normal books that I have read, but I also have latin books, french books, American Sign Language books (ironically), my complete set of books from my Master's studies, etc.etc.etc.
On top of that, don't forget to add knick-knacks. Awards, candles, and various other objects that act as really strong conversation starters. Again, with knick-knacks, make sure they have a good back story, ooooor at least, a good made up back story.
Comic toys, models, and various other nerdery is fine, but use sparingly. You don't want the woman to think she stumbled into a comic book store.
Worldly, think worldly. Don't think "random-mess-of-crap".