Henrik de Gyor blogs about digital asset management (DAM) software, but not specifically about their use in a library, museum or archive setting. Over the past year, he has included some interesting blog posts on why DAM software is needed, software features, and even DAM careers. Some will l find his latest blog post, How do I plan for a career in DAM?, to be of particular interest. I agree that there are a variety of way to become proficient is understanding, using and customizing digital asset management software. I don't think that Twitter, which he mentions, is really helpful for learning about digital asset management software, but do think it can help you make connections to other users as well as some of the vendors. He doesn't specifically mention on-the-job training or hands-on training, which may be a method that many use.
If you surf through de Gyor's blog, I'm sure that you'll find other blog posts that are of interest. You'll also note that he has run several polls. The polls that I viewed had limited votes, so if you find one that interests you, consider submitting an answer. More data or even comments on blog posts can be helpful. (Honestly, a poll can collect bad data if people answer just to see the numbers change. Thoughtful comments can be much more meaningful especially if the response pool is small.)