The easy answer is to ask ATC... "I'm not familiar with that type, could you give me more information?"
And you think we know. . . . ?
"You number two to a, er, [reads off the strip] XY97!"
"What's one of them then?"
"Er, a big plane with wings????"
But it is a good idea the grasp a basic knowledge of the more common types.
We don't go in for the absolute micro-differences between similar types. You call a PA28 to someone to be informed "I'm a PA28RRRRRRRRRRRRRRRRRRRRRR!", or "I'm a Dakota" at which point I use to say to the first "traffic in your left 11 o'clock is a DC3". Oh well.
VA