Having set quotas won't change a thing if the people in a given organization are backwards thinking. They will hire minorities, but that doesn't mean that they will change their mindset. Working in a place where people silently disapprove of you because of your nationality, gender, sexuality, disability .... is also not healthy for that person.
I'm not sure what the best approach is, but simply being aware that minorities and women are having a much harder time than average people to reach top positions certainly helps. Some of the most hardworking people I've ever met belong to certain minorities. However, I'm not saying that companies should hire people who don't have the necessary skills for the job.
In my previous company, we helped Rails Girls to hold free workshops for women, and some people from the company volunteered as mentors. This type of positive reinforcement makes a lot of sense to me. Also, I think that governments should shield women from getting fired when they get pregnant - which is a trend from all over the world.
Also, here's an excellent post from a woman who has worked for quite a while in tech in which she describes what she has gone through. Basically, speaking up at work when someone belittles minorities can help more than you think. Some people find it hard to find the right words when someone attacks them for no reason. I know I do.
I've been in situations where people talked thrash about LGBTQ people in general, and I've never found it hard to stand up to them. However, it took me years to learn what exactly to say those situations, how to keep my voice down, and how to behave and keep the discussion civil. And that's hard when you feel attacked and offended.
Be an ally and keep in mind that minorities often suffer from impostor syndrome, which makes it difficult for them to express how good they are for a certain position. I've personally gone through that phase and know how hard it is to get out of that mindset.
So, instead of just interviewing people, give them a task and see what they can do and if they're the right fit for that position, don't base all of your judgment just off of an interview or whether you'd like to hang out with that person after work.