There are two kinds of networking that happen at conferences. In the majority of cases, you meet a total stranger at lunch. You spend an enjoyable 10 minutes chatting, and exchange business cards, but there's no real reason for you to be in each other's lives. You don't work with similar tech or in similar industries or in similar geographies or whatever. Neither of you can offer the other much beyond conversation and friendship, but you don't instantly bond as friends. You add each other on LinkedIn and that's as far as it goes.
But sometimes, it goes a little differently. It turns out the other person runs a user group in your very own town, or in the town where your parents live that you visit pretty often. Or is running an open source project you've been thinking about contributing to. Or works somewhere that is hiring and came here to find candidates. Or just read a great book and wants to tell you about it, and it really is a great book. Or, because "what you want might be what I need to give", the other person might be thinking about speaking at user groups, and lives in the town where you run one, or visits that town a lot. Or is ready to contribute to an open source project and already knows about yours. Or is interested in a topic you care about and really wants a book recommendation. These conversations are golden. In twenty minutes your life can change.
Sometimes, the only difference between those two scenarios is luck: who you happen to speak to. Other times, the difference is knowing what you want. Do you want to learn more about something specific? Do you want to be one of those people who seems to know half the speakers? How about that person you know who does a web search for a problem, hits a blog link, and says "oh, this is XYZ's blog, good stuff, we can trust this one" and you wonder how it's possible to know all the bloggers and know which ones are well-informed and who works where and such? Do you want a new job, are you looking for a great book or a great course, do you wish you could blog or speak at user groups or contribute to open source? When you know what you want you are much more likely to meet people who could help you get it. Maybe that third person you spoke to knows a user group leader and would totally have introduced you, but the topic never came up.
You say "I never meet anyone who can help me with anything." Do you know what you need help with? Do you know what you want? That's the key.
Know what you want, don't be ashamed of telling people what you want, and talk to lots of people so the luck factor can kick in. Also do your networking in the right places. You mention talking to people at the same sessions as you, and that's definitely closer to the right place than the lunch table is - after all, you know they're interested in this topic. Get in the habit of evaluating "the room" to see if it's a gold mine of people who have what you want, and make an extra effort when it is.