Ways you've found for getting traffic to your projects?

I feel like nowadays there's a lot of often-regurgitated information about marketing online, but I'm curious to hear what you personally have found to work for getting traffic to your projects? Not what you've read that works, but something you've actually tried experimentally.

For me personally, I've found the following things true:

• If you run contests with physical prizes, you will get traffic, but I suspect most of it people who just enter contests all day as a hobby.
• For some countries you can still get traffic from Facebook ads at only 0.01$ / click to test things out.
• People are not as reluctant to share things online as you are. If you somehow incentivize sharing, many will do it.
• You can get massive amounts of continuous traffic (hundreds per day at minimum bids) from YouTube ads, but it's too expensive unless you have a very profitable thing you're selling (in my experience you need $50 LTV). Besides running the ad, creating it can cost as well.
• Writing articles really does bring in search engine traffic as everyone says, but is hit-and-miss and the trickle can be frustratingly low. I get hundreds of visits per month from my best articles, but most bring in close to none.
• Those "top 10... something something" articles often rank well and bring in traffic, but the kind of traffic that never buys anything.
• As an IH reader you know that "behind the scenes" type articles can do well (hit-and-miss though as everything) on link sharing sites, but I've found they won't bring in much search traffic. I've had many articles on top of HN, but they currently only bring in 50 clicks / month from search. It seems doing well on HN/subreddits doesn't really help with ranking on Google, except if some of those initial readers happen to backlink to it.
• Languages besides English exist. If something is hard to rank for on Google in English, it may not be so for other languages. Simplest way to get some (300 clicks / month for me) low-cost targeted traffic is just to describe your service in a blog post, then have it translated to a bunch of other languages.

I'll end with a Paul Buchheit quote and now invite you to share your own real-world findings.

"If someone says: That's impossible. You should understand it as: According to my very limited experience and narrow understanding of reality, that's very unlikely”