LinkedIn is fine, my past 2 contracts both were off LinkedIn
Yes, include keywords but spread them out, absolutely. Also include them in your cover letter.
Don’t use headhunters, but you can use recruiters.
Pick a specific tech stack to specialize in, one that is popular abd high demand. 100% yes you should have a portfolio using that tech you can link to on your resume or applications. Focus on applying to the smaller but refined pool of jobs that explicitly need the exact tech stack you have in your portfolio.
Example: I specialized in .NET tech stack. C#, azure, EF Core, NUnit, Sql Server, etc etc. The full windows stack.
It’s a super popular stack, and there’s tonnes of demand. I don’t waste my time applying for python or c++ or lua or go or rust jobs. I stick to my stack.
I have many projects on my github using that stack, including install instructions, releases, docker containers, etc etc.
As a result I can talk about the tech used in these stacks extensively, I know them like the back of my hand. I have strong opinions on patterns with them, I can teach others about them, etc.