With Tony, we had our first art-based lesson. He wanted us to do some observational drawing, so he took us all outside and told us to draw whatever inanimate objects we wanted. The trick was that we weren’t allowed to constantly look at what we were drawing. Instead we had to draw while we looked at our subject, which was harder said than done.
The reason behind this all is because when people glance at something then look down to draw it, they change it, they remember it in their minds but it’s never exactly right. So to get things more accurate you need to look more closely at what you’re trying to recreate. He also taught us that you need to do confident lines, even if they’re not perfect.