Design is a process, methodical in approach, focusing on outcomes with measurable goals that impact a product or service for the better.
If you’re building a product, you have to be great at saying No. Not ‘maybe’ or ‘later’. The only word is No. Building a great product isn’t about creating tonnes of tactically useful features which are tangentially related. It’s about delivering a cohesive product with well defined parameters.
You know that feeling when you’ve been working a long time on something, this is called burnout. You don’t have the energy to keep going, and you need a break. Some say that as long as you work normal hours, and not push yourself you’ll be fine.