Please note that Harry Potter is a fictitious story - there are no wizards in real life. According to the story, many wizards are not very comfortable with muggle ways, and often dress weird, even when they do an effort to look like muggles.
Apart from that - if the wizard in question has more experience with muggles - there is no way to tell them apart at a glance.
i want to be a wizard because then i don't have to do my homework. and i can cheat in anything
The answer depends on what you want tell it apart from!
a wizard
it depends what you are telling apart
yes
Meerkats tell each other apart with smell and dominant
Their eyes would glance at your lips alot while you are talking to them.
At first glance one can tell that 770 is divisible by 10 so it is composite.
Depends what "them" is
Nudge the container and judge the viscosity of the bromine.
you cant become a wizard. period.
As humans we have a hard time telling penguins apart. However, They can tell each other apart by distinct vocalizations.