When you target relevant groups and contacts, your meetings and referrals will be more useful.
If you find that your networking is producing very low opportunities for follow up and referral, try to improve your targeting. In other words, find different groups and methods. You can branch out to other types of referral or networking groups, maybe in another location. Or try getting a group of your trusted friends and associates together for a night of casual networking.
A true business network is a connected system of people within which referrals and opportunities can be passed through several connections, or circulated to all those connected. Networking thus can extend far beyond simply having lots of random one-to-one meetings. A given number of people who are connected for a reason will generally be more productive than the same number of random connections.
So don’t go aimlessly after every networking opportunity which comes your way; instead try to find networks which already function well or have the potential to do so; and consider and decide which sort of groups and contacts will be most helpful for your aims and capabilities – ideally remembering that you need to be able to help them, as well as they should be able to help you.