Starting from zero selling any product is a massive undertaking. The market you are thinking about going after is beyond saturated which means you are going to need to work even harder to close deals. Custumers are going to be price sensitive over what will seem like small amounts of money. Your team uses a tech stack that indicates they are generalists, which means you are looking at maybe 2 major customer profiles: pre-product dreamers with money, mid-sized non-technical companies looking to launch a product they don’t really understand. If your team doesn’t have an awesome portfolio, and hasn’t built projects for known companies, winning deals on price is probably your best bet. That lays the foundation for answering your question: where to find customers. Dreamers are going to be hyper-local. They want to meet face-to-face with the person doing the work. If you aren’t located in a major city demand is going to be low. Attending local startup events, business networking events, and industry meetups is a place to start. The other group can be found mostly at industry specific conferences, so you would need to invest money upfront to attend and build a network in a particular vertical you believe to be promising. You can try buying ads, you can try finding companies that already have crappy web/mobile apps, or messaging every person looking for a technical co-founder. None of those are going to make you very much money because your hit rate will be 1/100th of what you would expect. I’m usually not this negative but I can’t overemphasize how truly saturated this market is. You are competing with every freelancer from every country with an internet connection and decent English. I hope this is at least somewhat helpful for you.
Social is probably one of the most challenging spaces to raise money in. The general rule of thumb for investors in this space is 100k users with a proven growth channel where r0 is greater than 1 and their money is going to be like pouring gas on a fire for a proven concept. Almost every B2C product fails so investors are genuinely afraid to put money into unproven projects.
That said, crunchbase is your best bet for finding investors. Pay for a membership and search for companies that raised in the social space. Find angel investors that invested in those apps. You should understand all the companies in the social graveyard, why they failed, and try to have conversations with their founders. This will be the most promising channel for warm intros, which are the gold standard when reaching out to angels. Cold outreach will have a low hit rate but you will succeed every now and then at getting on a short call. Ask every person you talk to if they will intro you to 1-2 people that might be able to help give you guidance. Other than crunchbase you can try angel list. Avoid angel networks, they want guaranteed investments and will consume your time like crazy while they deliberate in DD, but you can reach out to individual angels with better success.
Remember, as an investor you see TONS of ideas. Maybe you make a few investments per year. Traction is the thing that matters most, not ideas. No matter how impressive an individual is, if they don’t have traction the answer will be “not right now.” They can afford to wait. It’s your job to show them growth that makes them feel that they can’t wait.