Steven Meisel, styled by Edward Enninful.

Gigi Hadid may be one of the most in-demand models today--this past season, alone, she walked for Marc Jacobs, Balmain, and Versace--but she hasn't always been confident about her career. "Obviously I’m not the best on the runway," she says with a laugh. "I'm still learning." That's the type of work ethic you can expect from Hadid, who has a reputation for being nice, responsible, and hardworking. Much of that comes from her mother Yolanda Hadid, who always said, "When you start working, you better be the most hardworking, nicest person in the room because if you’re not, then there’s always going to be someone prettier, nicer, and more hardworking.”

Here, Hadid reflects on her mother's wisdom, an unfortunate DIY haircut, and why she didn't become a professional volleyball player.

When did you start modeling?
I started when I was two with Guess and I think my last campaign was probably when I was 10 or 11, before I stopped modeling for high school and to do other things. I think my first campaign was when I was two, and I don’t remember this, but the night before my first shoot, I cut my own bangs. So in my first baby Guess campaign, I’m wearing a bandana because I decided to give myself a haircut.

When you were a kid, did you recognize yourself in the pictures?
There wasn’t a Guess store in the mall in my hometown so I feel like people probably saw it in magazines, but it wasn’t really like a thing that people talked about.

Did you go to your prom?
Yeah, I went to prom all four years.

What did you wear?
I wore my mom’s stuff to prom. I never bought anything for prom. I never owned anything designer until I started working. My mom had a beautiful closet and I kind of would play dress up, but she gave me an old vintage Prada bag for my 18th birthday and that was the first designer thing I’d ever owned. My senior year, I wore a red Herve Leger dress. Not the normal bandage, it was the one where they had the short sleeves and a beautiful braided neckline and stuff. I loved it. It was red, bright red and short. In Malibu, we wear short dresses to prom because we live at the beach. The long dress thing gets a little in your way in the sand and stuff.

They must have been nervous, the boys.
No, because I was just a girl they went to school with. Before I started modeling, I was more into photographers. I studied a lot how models made pictures in the sense that you have to be a positive part of a picture and make it better. And that’s what is really important for me on set. There’s some people that are bad at looking at monitors and some people that are good looking at monitors. And monitors really help me because I’m able to look at a picture and see where I fit into it, see what I can add to the picture instead of just being a person that’s on the page. But the runway thing, it’s funny because obviously I’m not the best on the runway. But what do you do? When you’re the face of a brand you show up to the show. My first show people were already expecting a lot more from me than I [was capable of at the time]. I never was taught how to walk on the runway. And maybe that’s because it moved really quickly for me, that people just assumed that that was something I knew. So, you know, a year and a half later, I’m still learning. I got some compliments on my Tom Ford show, so I’m getting better. I’m working on it, but I’m human. I still get insecure on the runway, but it’s really exciting for me because I want to get better. I love being on the runway.

What was the first big job you got when you decided to go back into modeling?
I wanted to be a volleyball player, [but] I decided to go to college in New York because I wanted to model. If I had decided to play volleyball, I probably would have gone to a UC in California or somewhere with a Division I volleyball team, but in New York, sports aren’t big at universities so I had to give that up. Obviously people weren’t paying attention to me at that point in my career, and I was doing everything that everyone does, all the crazy long castings, and go sees in weird places in dungeons in the middle of London where you don’t know where you are. I’ve done all of it. There was one point where my agent called me and he said, “Carine Roitfeld wants to meet you.” And I said, “Are you sure she said the right name?” Because, like, I have boobs and a butt and whatever, but so that day I went to meet Bruce Weber, Stephen Gan, and Carine Roitfeld. And that’s when I got my CR cover and then shot the Tom Ford campaign later that month and that’s where it started for me.

What’s the best advice you’ve ever been given? I bet it’s from your mom.
I think my favorite thing that she says is, “When you start working, you better be the most hardworking, nicest person in the room because if you’re not, then there’s always going to be someone prettier, nicer, and more hardworking.” And that’s just something that I always think about when I get to set. We all have off days and you’re sick some days and you’re tired some days, and we don’t have an office job where the person next to you knows that the day’s a bad day. It’s always a first impression and I think that the thing I try and remember is that you have to give your energy for that time because it’s the time that counts and that’s how the person’s going to remember you.

Were you always this responsible?
Always responsible, always really organized. [I’m] a little bit more lazy now if I’m being honest, but as a kid, like, I was very, not in a cocky way, but just sure of myself. I’ve just been comfortable, but maybe that’s why I feel like I’ve lived a couple lives.

Revisit Gigi Hadid's W cover story from the September 2015 issue: