Online dating has lost a lot of the stigma it once had, might be worth havign a mooch around and see if any suit you: there's ones specifically for geeks, for uniformed folk, for romantics, fetishists, older, ethnic...pretty much any niche you can think of, you can find somewhere with folk who'll share or embody your tastes. Plus the 'standard' ones if you don't want to narrow the field to one specific type. I looked around some, never signed up because I wasn't really ready to date until I bumbled into someone by accident, but it's dead easy to make a free account, browse a bit, and then only commit to a site once you've seen that there's a reason.
Also, look for events on your out-nights. Going down the pub for a few might find you a drunken fumble, but it's unlikely to give you anything worthwhile. The likes of speed-dating or singles-mingles can be fun, especially if you can convince a friend to buddy up (they don't have to be single, just someone to make you feel less like a pleb until you feel comfy enough to chat to someone). Even 'regular' events, such as concerts, comedy nights, game nights - whatever your tastes run to - are a good forum for finding people not just out to get sloshed, and have the added bonus of meaning they share an interest with you, and thus give you a simple conversation-starter ("I hope they play [song], that's my favourite. What about you?", or "Man, that was classic, reminds me of [other famous person], you like their stuff too?"). Local papers, websites, posters, all good places to keep an eye on for something like that.
Could even try taking up a new hobby, something low-cost time-wise. Setting one evening aside to go to trainign for a sport, or an activist meeting, or a game, or whatever, again leaves you with people who have a similar interest and should be happy to chat about it.
One thing though, don't go out there with the intention of meeting someone to replace that life-partner slot. If you're lonely and/or just wanting sexual contact, then you're likely to leap on the first glimmer of interest, whether you'd actually like them or not. Stick to casual dating until you're sure you genuinely like the person for themselves, and aren't being blinded by the desperate need to find someone. Go with the intention of making new contacts, or even just practicing the chatting-to-strangers lark, and if someone sparks with you, great, but if not, well, they'll have friends and open up a whole new social pool for you, or even just introduce you to new activities or interests that could lead you to meet someone else new. Don't put too much pressure on yourself, or them, and just try to have fun.