Ah, I see. Here, the yearbook image has to be a 2x3 inch photo, 1/2 inch form the bridge of the nose to the chin, both eyes visible, no hands to the face, no hats, no pets, no logos. Clothing must fit school dress code. That is a good thing as it gives the book a consistent look for the senior portraits. They are NOT formal portraits, and outdoor images are encouraged, but they are certainly not anything creative. In any case it is only one image - the REAL images are on the family walls. If one took inspiration from the yearbook images here, they would be dull, boring, and utterly lacking in style.

And you can tell the photos made by mom or dad or the "friend with a good camera."

Nightski-
the majority of my business is high school seniors. Use a focal length LONGER than 50mm if the image is waist-up. The 50 is fine for thigh-up or wider. With the lenses you have, shoot wide open, but be REALLY careful of focus - we want those soft backgrounds.

The background is JUST as important as the subject. A good beginner rule is to "shoot into the dark." Blown out backgrounds are seldom good.

If you use a reflector, NEVER allow the reflector to bounce light UP if it will create a shadow. If the reflector creates shadows, the reflector needs to be held HIGH so shadows go down.

87.368% of HS senior photography is connection with the kids. Anyone can put them out there and take a mediocre image. You need to SEE the connection they have with you and it is in their eyes. You need to keep up an almost constant banter with them. Make them laugh. Make fun of yourself. This business is less about gear and more about your connection with the subjects.

Under NO circumstance do you point a camera-mounted flash directly at the subject unless is is set to around a minus 2EV to be just a fill.

If you are nervous and tentative, it will affect them.

I am not the best one to give natural light advice as I always use a flash outside - either as a main or fill - but I do know you want to stay out of the direct sun except for that time just before sunset.

Feel free to check my website for some posing examples. Best to usually pose females so they are NOT square to the camera. There are exceptions, but just know that if you do it, you are adding weight to them. Having the body turned slightly (or more) away from the camera will slim them. Be clear you want earth-tone, solid colors. Anything can work, but medium to darker solid colors will keep the attention on the face and not the clothing. Good luck enforcing that!

Ah, I see. Here, the yearbook image has to be a 2x3 inch photo, 1/2 inch form the bridge of the nose to the chin, both eyes visible, no hands to the face, no hats, no pets, no logos. Clothing must fit school dress code. That is a good thing as it gives the book a consistent look for the senior portraits. They are NOT formal portraits, and outdoor images are encouraged, but they are certainly not anything creative. In any case it is only one image - the REAL images are on the family walls. If one took inspiration from the yearbook images here, they would be dull, boring, and utterly lacking in style.

And you can tell the photos made by mom or dad or the "friend with a good camera."

Here are a few practical ideas
1. You want to have the whites of the eyes showing on both sides of the pupil.
2. To get a pretty smile have her do a really fake laugh, and laugh with her, just as she finishes she is likely to give you that smile and look right at you.
3. Toward the beginning show her a really great shot.
4. If a pose you want to do isn't working, don't let her know you are stuck, she might think its her fault for not getting it right, just move on and skip it.
5. The body: if it bends, bend it.
6. See if you can give her something to do with her hands, like holding something.
7. Do not have her looking into the sun, it will cause her to squint. use the sun behind her as a hair light.
8. Shoot before 10:00 or after 6:00 to avoid harsh sunlight. The day before the shoot step outside every hour or so and note what time the sun has the best light. that is the time to set your time for the shoot.
9. you can buy one of those trifold science boards at walmart to use as a white reflector. Let her mother be your assistant.
10. You could buy 2 more. Glue some gold reflective material on one and silver reflective material on the other. You can probably buy it at walmart.
11. If you have to use that darn flash, set your camera and flash to fully automatic and let it be a point and shoot for a while. maybe not the best advice, but it will get you out out of a pickle.
12. Dont say oooops, they don't know you are nervous or something isn't working right.

Go have some fun

Something I do is after deciding on the location, I scout it the day before. Like everyone has said, shade is best so I look for the interesting "spots" to see when they are in shade. And I love the internet on poses so you can check that out. One thing a wonderful photographer told me was to watch for the "broken neck" pose. Be careful to not turn the head to the extreme. And have fun. I found it takes about 10mins. for you and your subject to relax. Oh and if she wears a necklace, have mom to keep a watch to make sure it hangs correctly. That sounds picky, but it will bother you later.

What really helps me (along with all the other great advise here) is to take my own kid or friend out a day or 2 before the shoot and practice in different spots in the park where you will be shooting. That way you will really know where the best light is and have a plan of action. Look for fence lines, bridges, or ponds to help with your backgrounds. Also maybe suggest a couple changes of clothes, cap & gown, letter jacket, etc.. And bring a prop or two..like if she plays basketball - bring a basketball to pose with that. I try not to pose the high school seniors - I let them kinda do it themselves and just make suggestions. They are very good at posing now with all their selfie practice.
Good Luck !!!