If you tried reading SICP in the past but it didn't quite click, you might want to try watching the lectures as you read it: https://www.youtube.com/playlist?list=PLB63C06FAF154F047
I personally thought the biggest barrier was the mundane, so I tried to write up some tips, test cases and helpful utilities for doing SICP ( https://github.com/zv/SICP-guile ).