Curious but how do you tell the difference between Saber and Mordred?

Aside from their clothes, I've noticed in some of the artwork that Mordred's hair is more of a platinum blonde. But I'm not sure how official that is.

There's also the noticeable one with Saber having a ahoge while Modred does not.

Seems also like more often Mordred has a straight ponytail, whilst Arturia keeps hers in whatever that bun is called.

Gollgagh said:
Seems also like more often Mordred has a straight ponytail, whilst Arturia keeps hers in whatever that bun is called.

Umm... I think the word you're looking for is "ponytail"....

No, I am certain that Arturia's standard hairstyle is not, in fact, a ponytail; I believe that generically calling it a bun would be more accurate than calling it a ponytail.

Gollgagh said:

Seems also like more often Mordred has a straight ponytail, whilst Arturia keeps hers in whatever that bun is called.

And Arthuria's ponytail in black suit in Fate/Zero is lower ponytail, not upper ponytail like Mordred. Also, Casual cloth of Mordred is more "naughty" than pure "innocent" like Arthuria.