First, it's good to have a niche. It makes it so much easier for you to find your clients. Just make sure there are enough of them and that they can afford you, as recommended.
There is no reason to network in person with complete strangers anymore. It's so much easier to meet the people you want to talk with online first.
The easiest way to meet people is on Twitter. The quickest way to find and consistently engage with the people you want to work with is by joining a regular, lively Twitter chat. Find a few local Twitter Chats (or local to your nearest metro area) in your service area here: http://www.tweetreports.com/twitter-chat-schedule/ . There are other listings, too, if you google them. Observe and decide which you'd be able to contribute the most value. Do so regularly.
Now at least some of these people know, like, and trust you, which is key to winning clients. They're not "cold" contacts and you can easily reach out to them via social media, and eventually take it offline when the opportunity presents itself.
When there are conferences you know some of them will be at, plan to go and let others know so you can meet them. This happens constantly on all social platforms and can lead to serious conversations.
No conferences? Every so often, you can use the twitter chat to casually ask if anyone will be in a particular area because you're like to discuss (topic) over coffee with a small group of likeminded people. These are also common ways to get to know more about certain people's needs and issues, leading to more serious conversations as well.
NEVER hijack a hashtag for a Twitter chat with advertising for your business. That's spam. Besides, people don't need you to tell them about yourself--they'll find out for themselves on your profile, and if they're at all interested by what they find there they will follow your link to your web property. So make it interesting.
Not keen on Twitter? Create a group on LinkedIn and invite connections you know would benefit. It's a little more work but it's worth it because as the owner of a group, you get automatic authority status.
Moderate it to prevent the flood of ad-sludge, link bait, and me-too content that overwhelms most unmoderated LI groups. Encourage discussion and relevant content.
Also, LinkedIn does not seem to promote its ProFinder feature very much (I found a writeup about it on an external site) but it's locally filtered. It will deliver requests for proposals/fee quotes to you based on services and industries you list on your account. Set it up here: https://www.linkedin.com/profinder?trk=eml-marketplace_provider_new_lead-null-0-submit_proposal
If you'd like to further discuss how to implement these ideas I'd be happy to talk.