Few iOS events are more tied to career development than WWDC. Before 2020, it was the only event that gave access to more than 5,000 developers and engineers in the iOS space. Several hundred of these folks work for Apple, one of the few times you can talk one-on-one with them.
Since COVID-19, WWDC has moved online-only. You won't need a flight, a hotel, or text your colleagues about where the Odwalla flavors are. However, WWDC still is one of your only chances to interact with Apple engineers. The opportunities are different but still valuable. And now WWDC is much less expensive.
If you need help convincing your employer to give you the time for WWDC, send your boss to the reasons to send your iOS developers to WWDC.
The first step to prepare for WWDC is knowing what technologies you and your business rely on. If your app is a game, you'll probably want to attend sessions on Metal or Sprite Kit. If you make an audio app, you'll probably want to learn about changes in AudioKit.
If more than one person on your team participates, you may wish to coordinate so that you can divide and conquer the conference.
I also suggest attending sessions that are less technical in nature. Marketing, design, and accessibility knowledge are universally useful to all apps.
Apple packs WWDC with events. It's critical to download the Developer app on the App Store and examine the schedule (when it's released). When WWDC was held in San Jose, a partially-obfuscated program was available in advance. Now that WWDC has moved online, only the Keynote and the Platforms State of the Union have released times. The Keynote contains some content for developers, but mostly it is at a level intended for the technology media. The Platforms State of the Union offers developers an overview of how to write software to take advantage of the new technologies. I would expect the full WWDC program to appear after the Keynote.
Tuesday through Friday is about scheduling tradeoffs. There will be multiple talks at the same time. Some of them might repeat later in the week. Others will not. There will also be labs that come and go through the week.
Some labs and consultations require you to make an appointment through the Developer app. They fill fast, so jump on them as soon as they open reservations.
You will almost certainly miss out on something, so know what your priorities are ahead of time. If colleagues or friends are attending, it's nice to make plans together. You can participate in different sessions or labs and compare notes later. Sessions are recorded, so it will be easy to watch the best videos in the coming weeks. You only get one shot at the labs.
No part of the conference is more valuable to a developer than the labs. The WWDC labs are where you can speak directly to Apple's engineers.
Making the best use of the labs requires you to do some homework: talk to your team and figure out if there are any technical issues you need help with. Did any of your colleagues file a Radar they want to ask about? Should they file a Radar? This is the time.
If there are new technologies announced at WWDC that you want to use, start implementing them immediately. When you run into trouble or have questions, look to the labs for help.
The labs are scheduled a day in advance since they have moved online. I suggest making your appointment request as clear as possible so that you get a suitable engineer assigned.
Sometimes the engineer may not be able to answer your question. Occasionally, the Apple engineer doesn't know how to handle the situation. Instead of giving up, politely request an introduction: "can you introduce me to someone who might know this area?"
Sometimes the Apple Engineer isn't even sure who might have an answer. If they don't know who can help, ask who might know the right person. It sounds strange, but they probably can find someone who knows more engineers. Who knows if this will be possible in online labs, but it's worth a shot.
Note: the labs fill quickly. I suggest requesting appointments early.
Apple has started operating meetups at WWDC. I'm not sure if Apple will attempt them for WWDC 2020, but third parties are hosting meetups regardless. If you're even mildly interested in the topic, attend. The social value of meetups usually outweighs the benefit of watching a session.
Meetups are a great opportunity to talk to as many folks as you can, even Apple employees. Treat everyone as if they might be a future life-long friend. They might be!
You can find a list of meetups here
The session videos usually make it online quickly, so there is little reason to take word-for-word notes. I suggest writing down new technologies or ideas that seem useful for your apps so you can follow up later.
It's useful to keep your notes searchable. I typically throw keywords into my notes, like important classes, frameworks, or demos.
Many developers feel reluctant to skip sessions at WWDC. There is a tradeoff. Do you want exposure to the new technologies so you can ask questions in the lab? Is it more valuable to spend time writing code against the betas? Of should you dedicate your time to as many labs as possible?
Personally, I suggest writing some code to test new technologies. There is no better place to try new APIs than WWDC. If you get stuck, you can schedule a lab appointment to get help from an Apple engineer. You can also ask for advice on the new Apple Developer Forums.
If you can walk out of WWDC with a working PR for a new feature in your app, you've done great! You can always watch a video later.
If work allowed you to attend WWDC, its essential to return value to your company and team. I suggest writing up a report summarizing what you learned, ideas for your app, questions you got answered, and any useful contacts you met at the event. Also, ask your team to message you if there are any technologies they'd like you to investigate.
When you return, consider demonstrating any new techniques you learned and sharing the demo code you wrote.