I used the official site, they cover most of basic stuff - then just read the API docs, and explore what others do in their components.<p>There are also some tutorials on codelabs <a href="https://codelabs.developers.google.com/codelabs/polymer-2-carousel/index.html?index=..%2F..%2Findex#0" rel="nofollow">https://codelabs.developers.google.com/codelabs/polymer-2-ca...</a>.<p><a href="https://polymer.slack.com/" rel="nofollow">https://polymer.slack.com/</a> - Join their slack channel for more information.