Have a portfolio, post free things on Github, write about what you do as a developer. Sometimes you have to pay your dues and do at-cost or volunteer work.
Is it better to have one big project in the portfolio or multiple smaller ones?
It's better to be well-rounded and doing projects that reach an audience. Maybe a couple small projects and a whale. Or a couple whales. Bonus points if you continue to work on that project for more than 1 year. It helps demonstrate your experience and value.
All solid advice. Involvement with an open source project with decent name recognition can give a leg up with all of this.
I would add to that, make sure your github account is listed on your LinkedIn or other profiles online.