With the vast amount of information available online, it's sometimes hard to see the forest for the trees, to distinguish valuable information from clickbait and junk. In the following I am going to talk about blogs, newsletters and books that helped me staying up-to-date. I hereby assume you already know the obvious ones like WWDC videos, the Apple Swift Blog or the official Swift Documentation.
I guess everybody starts out with Apple's Swift reference. Two years after Swift's official release there are a lot of books available. The main problem with these however is that most of them are either outdated due to Swift's rapid evolution or that they are targeted at beginners. The books I found most useful and go a step further are
Both are written by the same authors and they both take a look at the fundamental classes, structs & paradigms in Swift. While the former is mainly about a new programming paradigm - functional programming - the latter concentrates on the new stuff in Swift and how to use it in a Swift way.
Although there are a lot of Swift related blogs out there, not all of them deal with Swift on a day to day basis. My favourite ones that do are
Mike and Matt blog weekly but Natasha and Erica publish articles nearly every day. Since all blogs are available via RSS, I recommend to add them to your favourite news reader if you haven't already.
Due to the overwhelming amount of Swift articles, it's hard to find the ones that are worth your time. Give this Github site a try that references some of the best of them. I always find some really excellent articles there I haven't been pointed to via a blog or newsletter.
Those blogs I just mentioned and especially that Github site should already provide you with a good understanding about what is going on in the Swift community. Nonetheless I recommend not to miss out on the the good articles mentioned in the following newsletters
These are all weekly newsletters and they all differ in their release schedule e.g. Natasha sends out her newsletters on a Monday while Dave's can be found in your inbox on a Friday. If you already get too much email, just subscribe to Dave's. It's the one I usually enjoy the most (apart from Natasha's but you hopefully already got her RSS feed).
There are already quite a few Swift conferences throughout the year. So my recommendation is to definitely try to attend one of those. Of course this is not always possible. So if you can't make it to one of them, watch the conference videos which will usually be released a few days to a week later. The link I provided doesn't list all of them but if you subscribed to one of the newsletters above, there is I guess no chance you are going to miss out on any of them. Last but not least if you are looking for a specific video but forgot where you saw it then check out this site; you might find it there.
If you just want to consume video content, you don't have to restrict yourself to conference videos only. There is of course iTunes university which offers a lot of excellent online courses from various universities with the most prominent one being Stanford's iOS course. But don't make the mistake of looking only for Swift related videos. iTunes offers excellent math courses, courses about algorithms and software design. The content is provided by top universities for free. Definitely give it a try.
Apart from that there is paid video content out there as well. One of my favourites is Ben Scheirmans NSScreencast.
Everything's constantly changing. As software developers we have to keep learning. Apart from the resources I mentioned there are of course other ways to stay up-to-date. Is there a local Swift community in your city? Why not join them or if you don't want to leave your apartment why not join one online? Another option would be to do some pair programming. When was the last time you did that? It's not just an excellent way for improving code quality. It gives both programmers a chance to learn something new.
In general don't assume you know everything and keep on practicing new concepts. And while you are at it why not share and tell the Swift community about it? In other words: start blogging. It's a great way to practice and solidify your knowledge.