Re: If you won't look, you won't find the one.
I do have guys who would approach me, show interest, and then just disappear (and according to my friends, it's because I come across as having no interest). Truth is I keep a distance because I feel 'clingy' when I initiate conversations with someone, so I just keep away. I would ALWAYS ALWAYS reply to people's messages etc. but only when they initiate conversations.
Sounds like self sabotage - you're wary of becoming vulnerable/in a position to be let down. These guys you're supposedly "not giving a chance" - are they your type? When you mention initiating conversations, are you referring to the guys who have already approached you? Do you keep the conversation going with open-ended questions, or do you let them do most of the talking/emailing?
Paheli's got some good pointers. Be proactive, but avoid fixation with the word marriage. Don't view every Pakistani male you meet as a potential husband, nobody wants that sort of pressure. That's probably what's screwing with your head and compelling you to censor yourself. If you think you need to be 'chosen' by someone, you're more likely to modify your behavior so you don't appear 'clingy.' Instead, try shifting the focus from what he's thinking of you, to what you think of him. Be curious about what he has to offer you, and stop worrying about the impression you're making on him. (See how that's liberating?)
Be open to conversing with men you wouldn't normally consider your 'type.' Chemistry can grow, it's not an all or nothing deal. What you want may not be what you need. People have multiple facets to their personality, sometimes you need to prod a little.
I can think of a few couples where the girls initiated contact - the guys were usually passive and/or shy types. Their friendship grew in a group setting. The girls then nudged the relationship forward by asking the guy to call them/hinting they should explore this further/or brought up commitment as they didn't want the 'friendship' to drag on indefinitely.
My personal take on this, however, is that if a guy finds you interesting, he will find a way to approach you. My male friends seem to concur, and prefer doing the pursuing. This seems to ring true for men in general, and desi men in particular. If you're approachable, there's no reason why he shouldn't be able to initiate. If he's that shy, he can send his friend over, send you a message in a bottle, train a pigeon, etc.
I have friends inclined towards the written word who have found their spouses online - via blogging, or more recently eHarmony. As an ethnic/religious minority, there are only so many people you can meet in your social radius, so online networking is a popular option.
ps. Smile! And don't worry too much. It's called analysis paralysis for a reason. Not giving a sh!t is sexy =)