Well for me it depends on the other person.
I have few simple principles which I hold dear:
* Don't smoke.
* Don't drink too much. ( I drink alcohol ~1-2 times in a year, more is accepted of course by my future partner, but anyone who has a tendency to be drunk is automatically excluded. -_-;; )
* Accept my sometimes childish behavior.
This actually reduces the possibilities by a ~90%. ( Maybe a bad environment? D: )
But the remaining ppl have it quite easier.

If they can act childish to that helps lot. :3
Another point a view that I have never asked anyone out till now. >_>
Why? In middle school I had better things to do. I was too serious? Most likely. But I had 0 zero interest in having a girlfriend. My ex asked me out that time, now that was quite funny for me. Well I had a lot of new experience beside her, but I was right at that too that I don't necessary need a girlfriend. Not if she can't accept my lifestyle. ( Lost some friends because of her, wasn't able to go to the univ i wanted, had to skip many opportunities, and she became in the end narcissistic like hell....)
Now I don't want any again. I'm studying for exams, aptitude tests, looking for work till 2011 summer. Even later a girlfriend wouldn't be necessary for me. If I would find someone who suits me, then I would ask her out.
If I want to be an architect, then i won't have much time (here are just too many of them, if you want to be one, then you will have to give 120%, or you will fail).
Maybe a cute architect student :3
But who know what the future brings.
Lol... this became too long. sry. ^^;;