Ask HN: What should I freelance in?

Hi HN,

I just left my day job, and I'm now considering to be a freelancer. And my first question is: what should I freelance in?

- I know how to build and design websites (HTML/CSS, PHP/MySQL, Javascript/jQuery) - I know a lot about how to improve a website/app (UI/UX, conversion optimisation, funnels, AB testing, SEO, etc.) - I know how to build HTML5 games, and make them run as native apps on iOS/Android

So, what should I focus on? Which one of these skills is in higher demand, and can get me more clients at a higher pay?

Thanks!