Bootstrapping on the side is the best way to do it, so you can survive financially. I live off previous projects and consulting work while I try new side projects.
It sucks that you can afford less time on the side projects that way, but at least it's viable...
This feels like it was work sort of, but I was program director of my college radio station, WKDU in Philadelphia in 2005 or so. It was a volunteer position, and I was to oversee programming quality and the schedule, etc.
One of my duties was to randomly listen to radio shows to check for errors and issues, and make sure people are actually doing their shows.
We had a live stream, so I used some linux stream ripper and cron jobs to record the stream into 3 hour chunks (the default show length) and then time stamp them. This made it really easy for me to spot check shows and have a record in case issues came up.
There was one freshman DJ that I didn't really care for, and he had a 6am slot (It's early, but it's drive time, so you actually get a ton of listeners). He kept skipping his show and as the program director, that made me mad.
I ran into him one day and asked if he had done his show that morning and he said yes, and I was like "ok great!" But I went home and listened to his mp3... and he had not been on air.
Later at school I again ran into him, chewed him out for lying to my face, and then saw him crying afterwards.
For https://userinput.io (my service that connects you with reviewers on-demand feedback for your website, app or idea), getting on Product Hunt was the biggest thing. I got on Product Hunt nearly three months ago, and I still get traffic from there that converts. I was #3 the day I posted it. And yeah as other people have said in this thread, you need to know someone who can post it for you. I coordinated with an influencer that I kind of know, and he helped me out. My advice with Product Hunt is to post your project at like 1am California time, then start working your mailing list and social networks to try to get upvotes from Europe / Asia / Australia before Americans wake up, so that you have a decent amount of upvotes already, then just keep hustling getting attention to it that day. Be very available on PH to answer questions and respond to comments etc.
Early on, my first customers actually came from Twitter, which I still find surprising, but it worked. I simply did the "copy followers" technique of copying people who follow similar Twitters, and since they're probably interested in the topic of feedback, they would follow me back or check out the site.
Reddit ads also got a few orders, and are pretty cheap and interesting to try out.
Also I built out http://feedbacktools.org as a way to promote my own project and learn about a ton of other similar tools. It's basically just a small curated directory of every tool I could find that was related to feedback, but of course mine is at the top.
Also, a referral plan helps. I give customers a code that they can share with their friends for $10 off their first order, and anyone who refers a new customer gets a $10 credit.
It sucks that you can afford less time on the side projects that way, but at least it's viable...