OK, so we can tell what colors a person wears easily now. How about face, complexion, etc.? Or maybe just more details about clothing?
I can only speak for the signs/planetary influences of myself and the friends and family I'm closest with, but let's see if I can help...
First, I have to make a confession that's going to at first seem quite rude, so bear with me for a moment. I have sometimes casually referred to the trademark Aquarian eyes as "soulless Aquarius eyes" -- but not because I think Aquarians are soulless at all (they are some of my favorite people!). Basically every Aquarius I've ever known (and some Caps with strong Aqua placements) has had a gaze that seemed somehow... not of this earth (whether they had bright blue eyes or not). Of course Paul Newman is the EPITOME of Aquarius eyes, but one of my exes and my mother are both Aquas with dark brown eyes. In the case of my ex, he had the same intensity in his gaze, and in the case of my mom... I'm not sure if she LOOKS Aquarius or not, but she certainly acts like it (and with Libra moon, her double air combo is always crusading for truth and freedom and equality -- always rooting for the underdog and the forgotten sad souls among the masses).
Truth be told, I have this "soulless gaze" as well (but my eyes are almost black), even though I'm a Cap sun (but with Moon and Merc. in Aqua). So maybe this kind of look is what happens when Saturn meets Uranus? If it makes a diff... I have Saturn, Uranus and Neptune all in the 1st house.
Let's see, what else? Most Capricorn women I know hate having their nails painted, because hands are used for WORK and should be kept utilitarian. On the other hand, Capricorn men I've known can seem a little metrosexual in their grooming habits -- one would get very simple manicures (not painted nails, but just a nice file and trim and taking care of cuticles and such). In general, Capricorns are into a very natural look -- most of the women don't wear much makeup unless they really need it. Even if they don't have an all-black wardrobe to easily identify them, they don't tend to feel comfortable dressing too ostentatiously. Then again, I DO have an all-black wardrobe... but my goodness, it makes sorting laundry easy.
My Leo gal friends were the opposite -- they'd paint their nails in class in high school, and had different nail painting patterns and colors for every holiday and occasion. (I also had a Cancer best friend who felt incomplete without her fake nails and was similarly inclined.) While Leo does seem strongly inclined towards bright colors and anything eye-popping, I did have a Leo gal pal who loved the drama of dark-colored clothing. The MAIN concern among my female Leo acquaintances and family members is that regardless of what color they are wearing they look as fabulous as they know they are. My Leo Grandma would spend two hours getting ready every morning to go out and play bridge. She set her hair in rollers and the whole deal... and WOULD NOT leave the house until she had been properly put together. In contrast, the Aquarians I've known really don't always give a ****. They just want to get out of the house as fast as possible!
My triple Cancer ex did have an incredible moonchild face. He had a ski slope nose, round face, a totally compassionate oceany blue-eyed gaze. I look like the Wicked Saturnine Witch next to him. My female Cancer friends would be a little harder to spot just based on appearance alone. A common thread among all of the Cancers I've known, male and female, is PORTABLE PROPERTY. Some of my Cancer friends seem to live out of their cars and have everything they need in their trunk. Or their purse. Or their pockets. Their stuff doesn't just stay in their Cancerian caves, it comes with them!
I'll stop there for now, but I could keep going... lol. Get me on a roll and I don't shut up! ^_^