It's the hustle and the exposure. The more people know that someone like you exists and has "unique or special" skills or "is amazing and flexible to work with" then word of mouth will carry you a long way before you have to pay for advertising.
But remember, it's feast or famine.
And the moment you need to add employees and other people to the mix, be prepared for the complaints to start as just like when you have houseguests or someone borrows your car, it's never treated the same as you would treat it.
This issue above is really the limiting factor for most entrepreneurs because we're willing to do all the hats to get it done/sold.
An employee only has vestment up to their compensation and once they figure out what their time is worth, you are screwed paying more and more.
Finding solid people willing to do the job is what we site for the cause of shuttering a 35 year old family business as it was too difficult to hire and train and retain people constantly wanting to level up, or just get their buck for least possible effort/education or not discuss/engage more connection into the business and desire to grow it along with them... as that's how businesses are built, people get invested in it.
But I do keep a consultancy up and running even if idle. The business taxes and bookkeeping if idle can be automated and take seconds to do and it's a legal functioning producer of tax deductions in just maintaining it's existence.
I've gained more connection and "side" opportunity/money just networking and being open to offer sellable good products and forward thinking services for those that want a "solution" and a confidential, personalized service for "projects" or "consultancy" that needs a experienced individual to work with them addressing concerns you wouldn't want to get a RFQ or do a parade of estimation/bidding for.
But again, it's the hustle and contact that get you gigs.. gigs that all eventually end as time is money and when it's on their time, it's not your money anymore. Remember that. :P