I am primarily self trained and it took a long time to get "good". I wish I could have worked under a master, but that opportunity never arose and I was starting when web development was all new – so there were no masters.

Read and study and learn from your mistakes and the mistakes of others – you will believe things and realize later that your beliefs were wrong.

If there was one book I had to recommend that I have read it would be Sandi Metz's 99 Bottles series.

Oh, and learn multiple programming languages.