One thing I've found helpful over the years is mixing free and paid work. You can use them as a ratchet to work your way up the mountain of your career. In my experience you usually get paid to do what you don't love and you usually don't get paid to do what you do love. So if there's an area you're interested in you may need to do some free work there - an open source library, or offering your time free/cheap to prove yourself or learn. If all goes well, you have something in your portfolio you can point to and say - "I can do that" and some people you worked with who will vouch for you. It's a slow process and requires you to know what you want. Bottom line, if there's an area you're interested in and don't have experience there, you need to spend effort figuring out how to get experience there.