Online Marketing
You have a product and need customers - where do you find them?
Waiting Customer Problems
To answer this question, you need to be able to pinpoint which problems your product solves. Get really specific about it and then turn to your favorite search engine and search in niche online communities like Reddit / Twitter threads, YouTube comments and other forums for people in need of your solution (f.e. how do I sort my photo collection? etc.) and spread the message! So this is the easy part: the customer is actively seeking a solution and you can help out - a win-win.
Virality
Affiliate Marketing
Let influencers / customers directly profit from sharing and recommending your product.
Sharing
Build sharing functionality directly into your product, so that it can naturally spread.
Content Marketing
Blog Articles (SEO)
Publishing high-quality blog articles that lay out how problems / pain points of your customers can be solved using your product is a good way to but a long game. Your website has to built up reputation - so search engines learn to trust it.
Videos
Don't just stop with blog articles! Create short and long videos on platforms like YouTube and TikTok to engage different customer segments. Keep it short and simple.
Cold Leads
Write concise E-Mails / DM's to potential customers that clearly state which problem you can solve for them.
Paid Ads
Generally a hard game because the incentives are off. You want to only pay for engangement that directly generates sales (like you do with affiliate marketing).
Influencer
Finding a relevant influencer that authentically can promote and ideally regularly use your product is a safe bet to reach new customers.
Platform
Paying social media platforms to display your ads in social media feeds can work but is a hard game...