Prior to that I got interviews via Linkedin.
For small companies I look at https://angel.co . I have gotten interviews from there.
I got a job a few years ago from my local Craigslist.
If you go to Google and type jobs, it opens up their thing to look for jobs.
I got a consulting job from this (HN) website's who is hiring who is looking threads once.
I switched my IT specialty a few years ago and was just happy to be getting paid a few years ago. As I have been getting more experience, I have been looking at https://levels.fyi and have been looking at not only companies and cities, but even what positions are getting paid. I will probably move to a larger city for my next job.
All of my jobs have come from a direct recommendation from the head of the department. Everything else gets passed through HR and takes forever.
People find me, or I find them. We chat. Interview. Test. Offer.
Sometimes whoishiring is good for more niche jobs but don't post your email in plaintext. Use an alias, I've noticed certain variants of my email getting sold off to recruiter farms from here.
You want a LinkedIn just to show that you are a real person. Levels.fyi is a good resource for negotiating salaries and managing expectations.