In the thing that you use to pay your bills, become exceptional at it. Become the linchpin in your discipline. This creates job security but not in the boring, kafka-esque way that you’re allowed to rest on your laurels and continue to get paid. I mean job security in that you become known. People seek your opinion, your thoughts, when it comes to your domain. This creates leverage, which is an incredible asset. When you have leverage, you call the shots. You get to dictate the terms of the contract because they need you, not the other way around.
With credit to Seth Godin.
In the skill that you pick up, be sure it’s actually in demand and that people and organizations will pay for that skill. Otherwise, none of the above will be true. You may have a degree in philosophy and world history with a dissertation on the social implications of the Peloponnesian war but I assure you, outside of some niche museums, no one is going to pay you for those skills. Be useful. Be valuable. Be the linchpin.