What are some tricks to take good school-type portraits with a generic digital camera? I'm a noob?

lightning, even with the cheapest camera if you got good lightning it'll look professional,

try to avoid hard shadows, make sure you use soft lightning, you can use paper to soften out the light, so bright lights and soft lights, and make sure the whole subject is iluminated.

if theres no artificial lightning, natural lightning can do a pretty good job too, stand next to a window and the same lightning will bounce off the room and make a nice fill light, afterwards you can adjust un photoshop or any other software to add warmer tones to create a studio like feeling

If you are taking classed the teacher most likely would know. Also most of the ones people buy for their snap shots would not be very good for professional work. SLR digital cameras with over 12 mega pixels is the lower end of pro stuff. they are not cheap and the extra lenses are costly as well. As an armature then there are some good cameras under five hundred bucks. Just to have fun then a hundred would buy a cheap one. there may be some good used ones around as well.

You would need a basic 3 light system, main, fill and background, with a stop difference between your main and fill. What you use in the background depends upon what the school used and how closely you can match it. Most schools have a make up and retake day, couldn't she just go then?

well maybe hang a black bed sheet against the wall and set a stool in front of it

have the subject sit with his or her back straight shoulders back and have them stare at your forehead when you take the picture.

if you have two floor lamps put really bright bulbs in them and set them to the left and right of you

but not too close to the subject

if you dont have a digital camera borrow one

and take a picture with flash on and one with flash off.

just incase you dont already know, the flash is a lightning bolt shaped arrow.

my senior year in high school i rounded up all the kids who missed thier yearbook photos set up a spot in the auditorium myself and took all the photos it worked out well and they blended in with the other pics.

if this doesn't work or is not to the teachers liking

perhaps they can bring a digital camera and set aside a minute of time for you to take the pic.

i hope this helps good luck!