Jump shooting is a fine way to start out, most of us all either did it, or still do it!! Only way to really ID birds is get out there and experience it. I know from jump shooting myself, most of the birds will be flying away from you. Mallard drakes and hens are pretty easily ID'd, since the drakes will have white some white on the tail as they are flying away, hens usually do not.
Only thing that makes "jump shooting" or "pass shooting" unacceptable to me, is shooting at birds out of range. Just like guys who decoy, that shoot at birds out of range, same thing, sky busters.
Just gotta get out there and do it, learn as you go. You will make some mistakes and learn from them, it's the best way to do it.