Depending on the period of your embroidery, you need to understand the hairstyles, jewelry, ruffs, and head coverings to get your lady right. I have found many resources that I have shared with my students, but this one came up yesterday and I just had to put it out there. This blogger has cut out portraits and put them into lineups for every 10 years between 1500 -1700. Amazing. And you really get the flow of the changes as well as it makes it so much easier to interpret the lines on the draftings for motifs during this period. There is much more on the site.
If you want to look at lace collar styles for men and women, men's hats, and even a detailed diagram of facial hair on men for every 10 years between 1510-1690. Pick your decade and how to draw the face is right there for the picking! These are specific to France but the fashion did travel across the borders. And it makes it much easier to make sure that your figures on your piece are of the same time frame!