It is difficult. Quotas lead to resentment, and can result in the wrong person getting the job. They can also make things even more difficult for those who are selected, as people say they only got the role because they are female/black or whatever, even when it isn't true..
OTOH, without quotas how do you break the stranglehold of male white middle aged and middle class dominance, so that changes come from within? On a third hand (), it is not the role of individual employers to orchestrate changes in the whole of society - they have other things to do. Large corporations can be compelled to follow selection procedures, but small business can only be expected to comply with broad legal requirements such as equal ops.
I think that we can challenge sexism, racism, classism (another huge source of discrimination is social class) and all forms of prejudice when we see it, and bring our children up to do the same. We can challenge discrimination, but IMO that is less likely to succeed unless it is blatant (eg job ads saying no women need apply), as it is impossible to prove that the best person didn't get the job, and challenge can be counterproductive.