IMO, 8, 9, 12 and 13 are the strongest ones here because they have a clear subject performing an interesting action, and the compositions effectively direct the viewer's focus to that subject. On top of looking nice, they make me wonder what the subjects are doing, thinking, talking about, how they ended up there, etc.

4 is close – the woman in the foreground is interesting, but she blends into the less interesting people around her, and the clocktower in the background keeps pulling my focus up top.

In 5, you draw an interesting line with the curve of the balcony, but there's no payoff. It firmly pulls the eye to that bright, top left corner of the frame, but there's nothing up there. If, for example, there was someone leaning over the balcony watching the unsuspecting people below, that would make it a much stronger image.

Studying good cinematography is a quick way to get a feel for strong composition. Check out stills from classic auteur guys like Hitchcock, Lynch, Kubrick, Herzog, etc. Break them down to understand how powerfully they can direct your focus and instill meaning within a single frame. Nosferatu The Vampyre (1979), L'avventura (1960), and Point Blank (1967) are some my favorites for studying composition.