You could try writing an RFC or a tech spec sometimes with different approaches, proposed solutions, pros/cons. It's basically coding and designing the system in your mind and anticipating issues and challenges. It's a good exercise to do this before writing a line of code. The more you do it, the easier it gets, the mind starts to think about different approaches and pitfalls, you get into a focused state where the brain organizes the logical flow and then you can write a rough outline without caring about making the compiler happy or what the exact syntax is. Sometimes it also helps to translate this high level outline into pseudocde in a comment and then fill in the blanks with actual code.