Nothing can fully replace workshops and other direct teaching for immediate answers to specific issues and the chance to connect with other students and teachers. But there is a huge amount of excellent online resource readily available and, in many cases, free to access. There is also a lot of rubbish from people who claim to know what they're talking about, so it pays to choose wisely and not believe everything you hear.
As a guide, here are some of the best resources I've come across.
Mike Browne on YouTube
If you need to know more about aperture, shutter speed, ISO and some key photographic techniques, this is a good place to start.
Bridging the Gap by Adam Marelli
It's a one-off video for B&H. To my mind Adam too often ignore other critical elements of a great photo, but it's a very good explanation of compositional techniques.
Serge Ramelli on YouTube
Often over-dramatic processing but the demonstrations show the power of Adobe Lightroom and how to use it very well.
PHLearn on YouTube
A great channel for learning Photoshop, there must hundreds of high quality tutorials here.
Broadcasts a few free classes at any one time. You have to buy a class to be able to watch it at your leisure, but if you have time to tune in you just might catch some useful tips on the free broadcasts.
The Grid on YouTube
Good interviews and some excellent 'blind critique' sessions (seek out the Gregory Heisler and Joe McNally shows for example) on Scott Kelby's channel.
For a little inspiration.
Any other great free resources I'm missing? Let me know.
For anyone wanting to go further, I'm offering private 1:1 coaching at the moment, and have a street photography workshop coming up in New York in July. Details here.