What advice would you give someone who is starting their own company?

I wish someone had told me how much time it would take. I was so naive when I started my company, thinking that it would be easy to get off the ground and make a name for myself. What I didn't realize until later is that there's so much work involved in building a business and so many things that can go wrong. I'm grateful for my experience now, but if I could go back and tell myself something about starting a company, it would be: "Don't expect things to go smoothly. And if you had to pivot... PIVOT!"