A whole lot of the methods I recommend may use equally well for engineers who aren't making the change into direction, but I really do think the threat is higher for supervisors and so it requires more deliberate investment. Engineers that are spending most of their time writing code are still now learning, and are constantly reminded of just how important it's to learn new things.
However, managers can spend the majority of their time noninvasive problems, and therefore it's easy to under-invest in technical understanding.
The initial step is to convince your self that specialized knowledge is valuable to your career as a supervisor. Primarily, while I do think that good managers can still encourage a staff nicely if they are not technical experts in that field, all else equal, more specialized knowledge will make you a much better manager.
For starters, it will be easier for your team to trust you and find you commendable. It is going to also enable you to ensure that your team is creating the perfect technical decisions. Next, it is going to make it much easier for you to teach your staff, assess how they're doing, and instruct them to develop their own technical abilities. At length, especially in a field like software, there's a risk that the industry will "drift" and your knowledge will become stale. Therefore, even if you're in good shape now, it will nonetheless require continuous investment to maintain your level of understanding.
Next, you will need to find techniques which work for you. I find a mix of the following to be useful:
Spend 30-60 minutes daily reading.
Blogs and articles:
I use Feedly primarily with this, and whenever I find anything online (on social networking, etc.) that hasn't made it into my Feedly, I add the source to Feedly. I also basically have a habit that whenever I have any downtime I try to start my Feedly rather than social media. Countless posts make it to my feeds, although I only read a little subset of them, it's still beneficial to skim the headlines to find out what folks are writing about. This also works a bit like a "discovery" mechanism that will help me identify matters I will invest more in learning using a number of the techniques below.
More recently, I have attempted to find curated or community-based newsletters. To name some of my favorites, I utilize DiscoverDev, O'Reilly's Four Brief Links, also HNDigest (which is just a daily aggregation of the very best threads on HackerNews, like that I do not have to remember to visit it). Sites that have discussion threads attached to links are valuable for supplemental content and to help me evaluate the credibility of an article if it is on a subject I know less about. In case you have other recommendations, then leave them in the comments and I will add them!
There's always a small lag between what's occurring in the industry and what makes it into books, and they're also a bigger investment (of time and cash), so I use these mostly for meaty, much more evergreen content. Things like writing code that is clean, technical architecture, systems design, etc. are excellent book material. From time to time, books are also an excellent way for me to pick up a new technology (I populate the novel, and can use it to reference later), but if the technology is really fresh, technical proof might be a better way to find out.
Quora is also a wonderful place to find articles that are a little more accurate and less polished than books or blog posts. You might think I'm biased because I work here today, but I've always found it a useful source, although I joined the company (in actuality, it's one of the main reasons I was so eager to combine).
Talking to people:
I attempt to stay in touch with smart former classmates and coworkers. The principal rationale is mostly because I appreciate the relationships directly, but as a complication, it's a great network to tap into studying matters. Whenever we catch up, I try to ask them questions regarding how their existing company does matters, or what they're studying and if they have got any advice for things that I could learn.
Another terrific channel for learning new things will be interviewed. As a manager, you're likely interviewing different people from different businesses all the time. I use this opportunity to ask people what sort of stuff they're learning, how they have solved specific technical problems in previous roles, and also how they may solve certain technical problems I or my staff are facing at the moment. It is really a great way to both learn things, and receive a sign on what sorts of items a candidate finds fascinating and how they resolve problems.
I find it very valuable to carve time out to just write code and attempt new things. As a manager, I do not have as much time to do so in work (and also, I don't want to be restricted by my company's current projects), so I often do so out of work. For instance, things that I've explored within the past few months include Amazon's SageMaker, Terraform, Apache Spark, Apache Kafka, along with Golang. Sometimes it's only getting the tool set up and playing around with it, doing some tutorials, or building a fun side project. Trying things out helps go past.
I really have a whiteboard in the home next to my desk at which I manage a list of items I'd like to test out if I had more hours. That way, when I really do get that arbitrary downtime, I use that list. Random downtimes in my past have come in the kind of everything from canceled plans on a weekend, to being stuck at home because of very bad weather, thanks to being under curfew throughout the Egyptian revolution.
Meetups: I'd love to do a lot of these, it's just logistically more difficult than some of my additional methods, and that I haven't deciphered the best approach to create the most of the time that I spend on them.
Conferences: Even though I don't attend them in person all the time, lots of conventions will upload videos or even summaries of discussions offered there, and those have a tendency to be really valuable also.
Find something that is right for you. Different men and women learn in various ways, so in the event that you find it pleasurable, and can integrate it into your usual work/lifetime, you're a lot more likely to stay with it.