There are so many elements going on here, but they work because they are all very subtle. The shawl-collar top, the rolled up sleeves, the tucked in boots, are all possible because this gentleman from Milan paid great attention to detail.
These seemingly over-the-top looks are possible because everything about his outfit is subdued. What do I mean? Look at his clothes, they are all flat colors; no eccentric patterns, no powerful colors (though the pants offer a healthy amount of color, but they aren’t red). If you want to incorporate many elements without looking like a fool, make sure to use subtle patterns (if any) and make sure that there is a focus on the form of your clothes rather than their colors, if that makes any sense.
What I mean is, the focus of your outfit should be–if this was your outfit–the rolled up sleeves, the shawl-collar, and the boots; rather than making sure you’re wearing yellow, purple, and green. But then you’d look like the joker, so I guess you’d be screwed either way.