Here are two drawings based on pictures of real celebrities. The first is of my favorite Aussie male model, Daniel Garofali. The second is of the beautiful songstress Lana Del Rey.
Here's the DG pic. I usually like to use black and white pics to draw since you can see the values more easily. While studying the reference pic, I start off like most artists do with the basic shapes. Once I have those down, I usually go for the face. I love drawing eyes and I feel like the eyes are what makes the drawing really come alive.
While drawing this piece, I couldn't help but noticed bits of myself were being put into the face. Not intentional, but perhaps unconsciously. Overall, it doesn't look like him really (well the body does), but I still like this piece.
You can see the step by step process on my instagram: @ronnieboyjr
Here's the Lana piece. Now this piece look like her. But while Lana usually looks more stern in her pics, my rendition has more of a pleasant smirk.
I used my same method as the previous (and others like this). The hardest part for me was her nose. She has a high tip, which when turned to an angle and disappear under harsh light.
Overall, it's fun to study b&w photos, since they can help you understand value, and ways to simple create certain parts of the face, body, and more.