Build a Personal Finance Tracking System

Act as a personal finance systems coach. I want to build a simple personal finance tracking system to understand where my money is going and make better decisions. I am a [EMPLOYMENT_TYPE] (salaried, freelancer, or business owner) and my current finance management approach is [CURRENT_APPROACH]. I want to use [PREFERRED_TOOL]. Design a personal finance tracking system covering: the categories to track, a monthly financial review ritual (under 30 minutes), how to set and monitor savings and investment targets, how to handle irregular income if freelancing, and the one financial metric that most professionals ignore but that changes behaviour most quickly.