Every once in a while I'll get a new client that's a little worrisome of their upcoming portrait session. When I ask why, oftentimes the biggest complaint from clients is that they don’t like the way they looked in their photos in years' past. And even more often, this is because they learned (after the fact) that their photographer is (or was) inexperienced. Professionals in the field understand and are trained on how to make their clients look their best, through posing, editing, and coaching during the shoot. These key ingredients can make or break the shoot. Even before the shoot, are they coaching you on what to wear and where/when to shoot? Don't be afraid to ask these questions if they don't volunteer the info. When you invest in a professional, you are paying for their expertise and guidance to make you look the best you can, which is a factor that should be considered when seeking out your photographer.
When it doubt, don't be afraid to ask! Get the best "you" in your pictures.