How do you take reference photos? I'm trying to model my face on Blender using this tutorial and it gives links to reference photos.

The thing is, as I mentioned above, I want to try and model my face.

So I've decided to take photos of my face. But it doesn't seem to be working well (not symmetrical enough and stuff), so how exactly should I take my reference photos so that it would work well when I try to model it with the Mirror modifier?

Note: I only have the 'webcam' on my Macbook Pro and the camera on my Hongmi phone and I don't want to spend money on a new camera.
Use your phone camera, and hold it as far away as possible to reduce lens deformation. Hold the camera so the lens is at eye's height, as centered as possible. Cut the photo in two using gimp or other 2D software, and mirror it. Even professional taken photos have some non symmetricsl details.

Also take a shot in profile, at the same distance and height, and adjust to keep as close as possible the proportions between the two shoots.

Use the reference just as it is: a reference not a sharp point-to-point grid.