This info can possibly apply to the US as well as the UK.
I'm going to arrange the birds into eight different groups, according to Roger Tory Peterson :
- (1) Swimmers - Ducks and and ducklike birds.
- (2) Aerialists - Gulls and gull-like birds.
- (3) Long-legged Waders - Herons, cranes, etc.
- (4) Smaller Waders - Plovers, sandpipers, etc.
- (5) Fowl-like Birds - Grouse, quail, etc.
- (6) Birds of Prey - Hawks, eagles, owls.
- (7) Nonpasserine Land Birds
- (8) Passerine (Perching) Birds
Or, according to the Audubon Society :
- (1) Long-legged Waders
- (2) Gull-like Birds
- (3) Upright-perching Wader Birds
- (4) Duck-like Birds
- (5) Sandpiper-like Birds
- (6) Chicken-like Marsh Birds
- (7) Upland Ground Birds
- (8) Owls
- (9) Hawk-like Birds
- (10) Pigeon-like Birds
- (11) Swallow-like Birds
- (12) Tree-clinging Birds
- (13) Perching Birds
Within time, it will be seen that ducks do not resemble loons; gulls are readily distinguishable from terns. The needlelike bills of warblers immediately differentiate them from the seed-cracking bills of sparrows .
|Left to right: A gull vs. a tern.|
What is the bird's size?
Acquiring the habit of comparing a new bird with some familiar "yardstick" -- a House Sparrow, a Robin, a Pigeon, etc., so that you can say to yourself, "smaller than Robin; a little larger than a House Sparrow." .
What is its shape?
Is it plump like a starling or slender like a cuckoo? 
What shape are its wings?
Are they rounded like a Bobwhite's or sharply pointed like a Barn Swallow's?
- Note: I apologise, I couldn't find a Wikipedia Commons pic of a bobwhite flying
- ^ a b c d Peterson, Roger Tory (1980). A Field Guide to the Birds East of the Rockies. Houghton Mifflin Company. ISBN 039526619X.
- ^ Bull, John; John Farrand Jr.; American Museum of Natural History and Susan Rayfield (1977). The Audubon Society Field Guide to North American Birds: Eastern Region. Alfred A. Knopf, Inc. ISBN 0394414055.