Is there only one specific way to airbrush a photo? I mean I've experimented with Photoshop and I've looked at tutorials before but the way I airbrush is a bit different from how they do it. Does it mean because i do it my own way that it's wrong or what?

There's nothing wrong with airbrushing a picture the way you want. You do what you want. Really, if it looks good, then hell no it isn't wrong.