Take this with a grain of salt, as I'm currently in the same situation as you? These are just a couple of strategies that I'm trying (YMMV).
Option 1: If you're in college, look through the professors' web pages and look for ones who do research in areas that you are interested in. If you find one that you think would potentially make a good mentor, think of a SMART question to ask. It doesn't have to be anything incredibly difficult or profound; this is to show that 1)you are at least reasonably intelligent and 2)you are interested enough in his field of expertise to involve yourself in it outside of coursework. This is just the beginning of a process; all you're really trying to do at first is get them to think that you're not worthless. Having a little pet project that is relevant could help as it gives you a reason to visit and ask questions every now and then; if you are making significant progress, they will notice and you will hopefully progressively become less of a waste of their time until they warm up to the idea.
Option 2: Join a professional organization (IEEE, ACM, etc). Some metro areas have organizations specific to the local tech industry. I cannot vouch for this personally; I just recently became an ACM member but won't be able to evaluate its influence until the coming school year.
Option 3: If you live in at least a semi-urban area, check for tech meetups or events in your area or even try traveling to a couple. This might not yield a close mentor quickly, but the more people you know, the more there are that can potentially help you.