My friend's mom caught wind about my photography and loves my work. On June 3rd she wants me to take pictures of her daughter and all of her friends on her birthday. She's paying me, we haven't established how much-but this is my first "real" gig! I'm quite nervous, because I don't want to mess it up. Here are my questions. I don't have a speedlight for my d70 yet. Should I purchase one? She wants it to be outside in her backyard, and then later in the evening go to a lake in their backyard for some sunset pictures. Also, there will be about 6 or 7 of them. How should I take pictures of them all? Do I tell one person to put their arm on so-and-so's knee, or what? I've always taken candid portraits, where I didn't control any of their body positions. Secondly, I have a 50mm f/1.4, Nikon 60mm f/2.8 macro, and the 18-70 kit lens. What lens out of those three would you use the most? This is nerve-racking..