I've put together some tips for those wanting to improve their freehand drawing. These tips are also great for tracing techniques too - it's all about relative sizes, shapes and angles.
I mentioned a great video from Jason Morgan - the link is there if you wish to watch it.
https://youtu.be/lV7lbMghrs0
Regardless of how you create your outline, understanding how shapes and angles can help you with the perspective of features etc will really help.