First off, they liked to use perspective in their pieces. In particular one point perspective. One point perspective was first discovered by Filippo Brunelleschi, and italian architect whom built the duomo.
Another technique which was popular at the time was Sfumato. Sfumato was originally discovered by Leonardo Da Vinci. Sfumato is a technique that incorporates the blurring and softening of harsh lines and colours. Often used by painters for softening faces. One artist who used this technique was Johannes Vermeer in his painting for The Girl with the Pearl Earring.
The Girl with the Pearl Earring features a young woman in a traditional european outfit including a blue Turkish turban. Some of the things that make this painting successful, are its uses of principles and design. His use of a black background makes all of the colours pop in the painting. On the topic of colours, Vermeer used the fabulous technique of adding value to the piece, which in turn makes her look as though she is sitting right infront of you. Finally his use of rule of thirds adds intrest and pulls the viewer in to look more at the details.
For my renaissance substitution piece I selected The Girl with the Pearl Earring because of its intriguing features outlined above. About the process, I looked at the piece for a while trying to decide who would best suit the position for replacement and then I realized the model for this piece is around me everyday. My sister seemed to look identical to her. Once I shot an image of her against a blank wall, I dropped it into photoshop and played around with the features. This was the final result :