Congratulations on your new endeavor. It sounds exciting. I run a white-glove Arabian Gulf business development firm and while there are a multitude of tech tools to help you reach individuals--I am also a partner in a digital strategy firm--I have found that one of the best ways to find clients is through targeted networking and word of mouth.
Here is what I did: First, I developed a website (this was important as it helped me focus my thoughts) and then I sat down and made a list of everyone I knew who I thought would be willing to help me. Second, I culled those individuals' social media and professional pages and created a file on each person--who do they know, professionally or personally, and what expertise do they have. Third, for each person, I wrote down what my "ask" would be. The more specific and focused your ask is, the more likely you will get a response. Fourth, I prioritized my asks and then steadily worked down my list by having coffee/lunch with each person to let them know what I am doing, how excited I am to do this (people feed off of your excitement) and if I thought they were receptive to my idea, I would give them my "ask." Fifth, I focused on a win-win, which meant I never finished a coffee without asking the individual what can I do for them in return. Concurrently, I started to put together a list of trade associations, companies, government offices/officials, etc. that I knew could assist me but I did not have a natural in with and I approached them via cold-calls.
In your specific case, a few good places to start are befriending career counselors at your alma mater or at universities near you. Next networking at places such as your local rotary club, place of worship, country club, etc. Further, you may wish to consider getting an office at a coworking space like WeWork. Coworking spaces are great for meeting new people, especially through the various lunch time classes they host. Career transition classes are always popular and seem to be right up your alley. Finally, as someone else mentioned below, it does not hurt to host podcasts or blog tips. This will help further establish you as an expert in that field. Hope you found this helpful.