The letter to your future self is a 10x unlock for life. The process of writing a letter forces deep reflection on the present and thoughtful rumination on the future.
Use a baseline time horizon of 5 years in the future, but adjust as you see fit. A basic letter structure to follow: (1) Reflections on the Present, (2) Changes to Make, (3) Goals for the Future, and (4) Fun & Crazy Predictions.
I handwrite the letters and store them in a cabinet, but if you’re looking for a more technology-enabled solution, there are tools like FutureMe that should do the trick.