Since I already had a 3/4 view, I started with the side and front, but when I finished them, the volumes from the front didn't seem consistent with the 3/4. The center line looked off. I was estimating and eyeballing where parts needed to be and I wasn't happy with that estimation. I thought if I did a top view it might help me to better visualize how the parts of the face related to the front and side. When I finished though, I realized I could precisely determine where parts would be in a 3/4 turn by simply rotating my top view 3/4 then cross referencing that with the side and front views. It was especially helpful in determining how much something would shrink as it got farther away from a viewer.
I applied this trick. Then I realized that I could cross reference a rotated side view with a front view to make a more precise top view. I went back and did that (luckily, it didn't change the 3/4 I had already done). I further applied this trick to an upward 3/4 as well. A common trick for creating back and back 3/4 views is to silhouette the front and 3/4 views respectively and I've done that below.
My rough designs, drawing through the character:
My final, inked results with angles explained:
This character is supposed to be a scraggly, wiry character and I wanted to reflect that somewhat in the design elements. You may notice things don't line up exactly at every single point. That's because either it was a design choice in that I wanted to avoid a tangent or liked the asymmetry of matching elements; I have imperfect strokes and the width varied (again, I like this for the character); or because I was subconsciously making excuses for not fixing minor things.Given that points match up better than I could do without using this method, I'm okay with minor imperfections and I'm confident that they'll never be an issue in a 2D animation or 3D model.
By starting with a front view, then lining a side view up with it, I can extrapolate most of the other angles I need by lining them up with other, sometimes rotated, angles.