Hi Claudemir,
Good question! I love to take photos against the light as you noticed
Here you can see the direct light of the sun on her shoulder on the right. I asked one of her brothers to hold a white sheet on the other side to bring a softer light in the shadow.
When you have the chance to have someone able and willing to give you a hand during the photo-reporting, it helps a lot. For a dog or a kid, you can ask your assistant to create a white reflection in the eye. It will enhance a lot the photo and the portrait.
Most of the time, I prefer that the "subject" look at someone or something but me. One of her brother looked at me if you saw that portrait (my favourite) and he was more or less defying me.