The best detectives in DC Comics are typically said to be Batman, the Question, Detective Chimp, and Batman's many wards, not Wonder Woman. However, Diana has also proven that she has some stellar detective skills as well. Wonder Woman #109 from 1996 showed just how capable of a detective she is when it comes to spotting imposters.
The Justice League has been working together since 1960's The Brave and the Bold #28. The lineup then was largely the same as it is now, with Wonder Woman, the Flash, Martian Manhunter, Superman, Aquaman, Batman, and Green Lantern all teaming up. Since then, the team has been a DC staple, taking on the biggest threats and saving the world repeatedly. Considering their long history together, it's no wonder that they know all the ways to tell each other apart from imposters.
Wonder Woman #109 was written, illustrated, and inked by John Byrne. In this issue, the titular heroine comes across the Flash in Gateway City - her former main city of operation. However, something isn't right about this Flash. Wonder Woman is usually known for taking on mythological foes like Ares or Circe. She is often called in as a heavy hitter and is great in situations that showcase her Amazon value system. In this instance, however, she uses her eye for detail to notice that the Flash she's facing, isn't actually her usual teammate - based on his costume.
Both Wonder Woman and Wonder Girl notice that this Flash isn't quite right. The costume is similar and the powers being exhibited match his, however, Diana knows it isn't Wally West. Certain aspects of his costume aren't right. In the left two panels above, some discrepancies can be seen when compared to a panel from The Flash #117 - also published in 1996. The imposter Flash's symbol isn't at the right angle nor does the points on the bolt match. Additionally, the waist stripe is too linear on the imposter. The real Flash's stripe slopes down and inwards. One other major detail is the presence of wings on the imposter Flash's boots. These were not part of the Flash's uniform at this point in time. The Flash at this time is Wally West, but this imposter is imitating Barry Allen.
The imposter turns out to be a synthetic clone created by a computer. The uniform is put on its version of the Flash matched Barry's, down to the winged boots that pay homage to the first Flash - Jay Garrick. Wonder Woman has worked with both Barry Allen and Wally West for many years, so it wouldn't be unfathomable to believe she could mix them up sometimes. However, she demonstrates that she knows exactly who is supposed to be wearing the mantle now by recognizing the minor differences between their suits. She also recognizes that his abilities are being used in a very amateur fashion compared to normal. Wally may not be as experienced as Barry, but he's had quite a bit of time to finesse the use of his powers. These are definitely things that Batman would have noticed, given all the contingencies he has had in place to take out his own team if necessary, but Wonder Woman is just as astute in this situation. While Batman and other heroes may be better DC detectives due to their continuous use of the ability, Wonder Woman definitely shouldn't be undercut in this area.