Both of those definitions have the same opinion about being hipster...and that is that it outside the social or cultural mainstream, that it is usually outside the box and different than everyone else. There is also another perspective on hipster. Hipster can be seen as super trendy or the coolest thing to be wearing at the time. When I say trendy, I mean the kind of trendy on magazines, or catwalks or photo shoots. The cool styles that look trendy and hipster, but isn't something you'd think to wear often, in case you may stand out...but that's the best thing! You want to stand out! You want people to notice how incredibly hipster you look in those jeans or colette pants.
But the thing is, how can you be hipster? To start, you can be inspired by other hipster people and how they dress to get an idea of how hipster you want your style to be and so you know what to wear. Just looking at photos or reading through magazines can really give you an idea of what a hipster style is, and from there you can decide whether the hipster style is for you.
After looking at photos you've probably started to develop some sort of an idea about what you want to wear and what you want your style to be. The next part is finding a good place to find the right clothing.
Once again, hipster may not be the look for you and that's completely fine as there are so many other styles and trends out there which could suit you way better. Fashion is all about experimenting, you try different looks all the time, until you find your style, your trend, your look.