Early on, I did a bad job of defining the role I was hiring for. It was hard enough to drag one of my friends in to help with something, that I would accept anyone with a heartbeat 
The biggest thing I had to get better at was recruiting, interviewing, setting the correct expectations with clear job descriptions, 90-day plans, measurable metrics, and regular communication to check progress against those metrics.
In the past I’ve hired people and knew they weren’t the right fit, but “dealt with it” for too long because the idea of finding a replacement seemed too daunting. Early on with Trainual, I let someone go after 3 days when it didn’t feel like the right fit, so I was at least getting more decisive. Our 15th employee was a head of people operations, and since then we’ve gotten extremely efficient and effective at building a rigorous hiring process (more on our blog!) so that the team members we do bring on are excellent.
During my high school years, I started by doing all the work. If you’ve ever read the E-Myth, I was the technician. But when I went to college, I couldn’t go to class and do the work too, so it forced me to delegate. I think this was an extremely fortunate lesson early on in my career that a lot of older entrepreneurs struggle to learn. But the sooner you can stop working on the day-to-day tasks in the business, the sooner you can focus your attention on solving the breakthrough problems that help you scale.