First of all, I always make sure I have different textures of fabric when I'm wearing an outfit like this one. It makes it so more edgy, and alive- the outfit would look totally flat if I wore a cotton jacket with this instead of the leather right? Or is it just me? Leather, wool and cotton- the perfect combo! With some silver details of course.
Second, I bet you all know black is more slimming? Use that to your advantage. That's why I love skinny black jeans, pared with a fitted turtleneck and leather jacket you're ready to go. Of course, I'm not saying that oversized is a big NO- fitted is just what I usually feel most comfortable in when I'm going for all black! But I would definitely wear an oversized black shirt, or maybe a dress- it depends on the mood and how I feel that day.
And last but not least, own it! I mean, rules are meant to be broken right? Don't listen to rules unless you want to, the most important thing with fashion and how you dress yourself is how you feel- if something makes you feel good, go for it! There's been so many times I've gotten looks and stares, small (not so nice) comments on what I'm wearing, but don't mind that- I wear what I feel like wearing, and I'm going to rock it no matter what!