My favorite vintage style embroidery patterns are "Aunt Martha's". I've seen them at Hobby Lobby, or you can find them at http://www.colonialpatterns.com/.
I have been able to find all of the patterns I grew up with. My mom and great-grandma embroidered a lot. The fill-in trick I learned from Aunt Liz.
I liked this picture, and it wasn't an iron transfer, so I used a Hot Iron Transfer Pencil and traced the whole thing. (Always put an old tea towel or something flat to protect your ironing board cover. This is a "seep through" project.) Also, slip the shirt on the ironing board so you're only working with the front.
Then, iron on a semi-high cotton setting with NO steam for about 10 seconds or so. See how easy? Remember, your image will go on your project in reverse.
While it's still a bit warm, color it in with crayons. No need to be too precise, but stay inside the lines.
I like to use a bit of lightweight fusible backing to keep the embroidery looking crisp on the shirt. I don't use it with pillowcases or dishtowels, however.
Next, take a lightweight paper bag (I like the ones from Roberts Crafts that they use for your scrapbook paper purchases.) Place it over the top of the shirt where your picture is. The fusible backing is ironed on at this time too, under the shirt behind the picture.
Iron away! Again, no steam. You're trying to melt the crayon wax into the fabric, essentially making a stain. You'll see the crayon seep through the paper, and you're done.
Then, go ahead and embroider! Everyone has a different style. Just do what you like. I try to keep mine as just an outline, but I sometimes fill in middles of flowers or eyes. The stitches I use most are the Lazy Daisy and the Vine Stitch. There is a good stitch guide HERE.