HN user
The hardest part of learning any creative skill is that your taste develops faster than your ability. You can see exactly what's wrong with your work but can't fix it yet. That gap is brutal but it means you're improving even when it doesn't feel like it.
Went the opposite direction for a while, two monitors, then came back to one. The context switching between screens was costing more than the extra screen real estate was giving. Single monitor forces you to be more deliberate about what deserves your attention right now.
Switched to requiring 50% upfront for any new client work. Lost a couple of prospects but completely eliminated late payment issues. For smaller projects I just go full payment upfront now. The clients worth keeping never push back on it.