One piece of advice I dole out regularly:
"Trojan horse the thing you want to learn into whatever it is you've been asked to do." (THTTYWTLIWIIYBATD for short)
I wanted to elaborate on that advice a bit today.
The Trojan Horse is a story about how the Greek army snuck into the heavily fortified city of Troy. Here's a historical re-enactment:
Okay, jokes aside - what am I getting at?
You go to work and someone will ask you to accomplish something, like "Prepare a report for me about our projected spending."
One way to do this would be to pull the report yourself, or maybe ask someone to help you with it. Job done, hands dusted, problem solved.
Instead, THTTYWTLIWIIYBATD proposes you solve the problem by learning something new. This doesn't mean "shoehorn client requests into your current interests". Done correctly, no one should notice anything1.
Don't just pull that report - try learning how to automate it, or extend it, or prepare it a different way, and so on.
Knowing what you want to know is a skill in itself. Some helpful prompts to get you started:
Start with a straightforward pitch; you may be surprised. "I'd like to use this opportunity to learn a little about X." If they're not on board, knock out the request and next time do it without asking - just don't get caught!
Okay, not every request, but do be aggressive. You'll get a feel for it as you go - sometimes, life will get in the way. Also, don't be dishonest - e.g., don't inflate the bill for a client because you want to spend more time learning a new trick.
Well, yes, and you'll have to be mindful of that. The reality is you'll probably end up working longer hours when a new skill is taking longer than you intended to develop. Keep your lines of communication with everyone open: this is taking longer than I wanted, here's why, I'll keep you posted.
And that's it - the THTTYWTLIWIIYBATD philosophy. As you develop this skill, you'll get better at identifying the opportunities to learn. And as you learn your career opportunities will grow, too; by making my job my education, I've taught myself into many awesome career opportunities and a lot of interesting experiences to boot.