Photographers know the importance the focus of lighting . If you're still uncertain, ask for a soft filter to flatter your facial features and tell him or her which angle you prefer. Don't hesitant, You hired them and it's their duty to make you happy -- but always be open to suggestions. They know that the more pleased you are with your photos, the more you'll buy.
         If you're having your pictures taken outdoors, avoid direct sunlight and don't look sideways. If it is not a scheduled event like wedding etc, don't hesitate to reschedule the event, if the weather isn't favorable. Rain, clouds and wind may ruin your chances before you've even begun.