Yeah, sunglasses are tough to use like that. I am trying to find the feature I wrote for Ponds USA Magazine a few years ago and they don't seem to have any material on line. I'll keep looking. In the meantime, your camera phone should work with patience. Not sure about action shots with a camera phone. I think there might be 'shutter lag' that is, a slight delay between when you push the shutter and when the image is actually captured which results in a blur. I could be wrong about that because I only use an DSLR for images. White or black poster board blocks the sun well. White is great for 'filling' shaded areas because it reflects light into those areas without causing glare. Often you can use the reflected light from the poster board and not need a flash. Also, consider using an umbrella. Umbrellas work quite well. It helps to have someone else hold the umbrella or poster board. I found capturing images to be best during dawn and dusk for great contrast and control of reflections. Also, wear dark clothing and gloves to help keep yourself out of the images. I went so far as to cover the brand name which is in white letters on my DLSR because it showed in photos. Go figure, they go to great lengths to make the camera produce beautiful images and then put print their name on it to reflect! A dark case for your phone camera will help avoid reflecting it into your images. Anyway, you can try the above and let us know how it works.
Stephen