Shooting in the yard?

I'm no pro by any means, but my mom wants me to take pics of my sister. I really want them to come out well. She'll be turning 16 and getting ger braces off and I'm sure she wants them to look well too. From the lenses listed in my sig what should I use?? I'll be shooting around my parents house. Here's some pics of the area. Suggestions on locations, time of day? Also, should I invest in some kind of reflector??

Front Yard(house faces southeast)

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

I'd shoot 70-200 and 50mm. 1-2 stops from wide open, so say F4, to give sharper results, but still a tight depth of field.
A nice house.. Maybe get her around everywhere green, and also sitting on the deck railing, with her back/head against the support.

Thanks for the tips. Don't think I would've thought of the railing.

I see lots of trees around there... Make sure that if she is in the shade, she is in the shade all the way. Sun spots are distracting.

But good luck. Have fun and learn as you go.

Also, if she is in the shade you may want to use a fill flash.