AMKE head different angles ref

American Kestrel (Falco sparverius) head reference, modeled by two education birds, a male (orange body) and female (striped body). Falcons belong to the order Falconiformes and are more closely related to parrots and passerines than they are to the other diurnal raptors, the hawks, eagles, harriers, vultures and kites of Accipitriformes.

If you're drawing a falcon, the major visual difference from an Accipitriform raptor will be the shorter, more strongly curved beak with a pronounced tomial tooth. The tomial tooth is the pointed notch right behind the tip of the upper beak [link] . Falcons frequently kill by impacting their prey at a high speed, but if their food is still alive after being struck at 100+ mph, falcons use that tomial tooth to sever the spinal column. Falcon nares (nostrils) have a visible little tubercle/baffle as an adaptation for diving at such high speeds. Another thing that makes falcons so fast and maneuverable are their long, pointed wings. Finally, falcons tend to have a rounder head and larger eyes than Accipitriformes. This trait is especially pronounced on small falcons like the American Kestrel, but I included photographs of three other species at the bottom to show how larger falcons look. From left to right in the last row are two American Kestrel chicks (female and male), a Merlin, a Prairie Falcon, and two Peregrine Falcons.

Some of my other references
Red-tailed Hawk: [link]
Golden Eagle: [link]
Great Horned Owl: [link]
Barn Owl: [link]
Burrowing Owl: [link]
Turkey Vulture: [link]
Icterid (Brewer's Blackbird): [link]
Raptor Feet: [link]