https://hi.hyperskill.org/
^This might be a good place to learn the intermediate stuff. Python, Java, Kotlin.
More intermediate stuff goes into the data structures and algorithms.
https://sp19.datastructur.es/
^UCB's Josh Hug is a good lecturer, also provides course textbook, hw, side projects.
For best practices, try to get the Head First Design Patterns PDF.
Common mistakes? Search for "Effective <whateverLanguage>" and you should find a PDF for whatever you're looking for.
Also, goalkicker.com has compiled a lot of intermediate stuff from scraping StackOverflow question-answers.
More intermediate stuff goes into the data structures and algorithms. https://sp19.datastructur.es/ ^UCB's Josh Hug is a good lecturer, also provides course textbook, hw, side projects.
For best practices, try to get the Head First Design Patterns PDF.
Common mistakes? Search for "Effective <whateverLanguage>" and you should find a PDF for whatever you're looking for.
Also, goalkicker.com has compiled a lot of intermediate stuff from scraping StackOverflow question-answers.