Some of those can be changed in the Android Wear app...
Go into the Android Wear app, tap MORE to the right of watch faces, then tap the three little dots near each watch face and select settings.
Some of the watch faces, like "Digital" have to be customized on the watch itself. To do this long press on the watch face (as if you wanted to change your watch face), then select the little gear icon under the watch face. This doesn't appear on all watch faces, so some discovery is required.