You just need to throw enough shit at the wall until it sticks. If you are only talking to 10 people a month, and you close a deal with 10% of them, that's 1 new client a month. Assuming you can maintain an ongoing relationship with each client, that could well be enough. In my experience it's better to have 3-5 continuous clients than it is to be finding a new one every week.
Beyond that, my advice:
- SPECIALIZE. Pick one skill that you are very good at (sounds like it's conversion optimization) and focus 100% of your energy on landing clients who need that skill. For you, conversion optimization is a particularly marketable skill because it has a direct 1:1 relationship with value you can provide. If you increase conversions by 1%, that has a real monetary gain associated with it. Set your prices based on this value.
- Sell yourself. You are a product. Convince your client why it is valuable to his business to hire you.
- Always be getting leads for new clients, even when you're working on a project for another. Close the deal and then worry about scheduling.
- Consider working at a "discount" for the first project with a client, or a differing pricing structure, then raise your rates. For example, I like to start projects with clients as fixed price, in order to build trust and a sense of my working pace. Then I move to daily rates.
- Join any slack groups and skype groups you come across. You can find some skype groups on internet marketing forums, and nomad list has a good slack group (thousands of entrepreneurs in it)
- Consider reaching out to consulting/freelance agencies and offering your help on any projects that require your specialist expertise. If a consulting shop is good at fullstack development, but not at conversion optimization, then that's an opportunity for you.
- Update your linkedin saying you are accepting clients and new work. Make a list of startup founders in your network, and get in touch with them via personalized emails describing how you can help.