Make sure that both, you (the model) and the photographer are absolutely clear about what type of work you will do. Portrait, clothed, figure, topless, nude, or a combination?

If terms such as 'beauty' or 'glamour' are mentioned, query what exactly the photographer means because it can mean, literally, anything. Where will the shoot take place? Are you expected to model together with other models and what exactly will it involve? Will there be suitably private space where you can get changed?

Agree beforehand what you will and won't do. On the day of the shoot, do not change your mind and do not refuse to model for a style that you have previously agreed to, unless you have a seriously good reason. Second thoughts is not a good reason.