Sort out structural issues like long pay scales (which is one of the reasons pay gaps open up in supposedly egalitarian workplaces like universities). If it takes, say, 7 years on average to reach "rate for the job" and a woman has two breaks for maternity leave (getting a nominal "meets expectations" in her annual review for those years) she falls behind her male cohort. Realistically for most jobs it takes a year to learn the ropes, another year to get good at it, and by year three you should be doing it well - no need for a seven year long progression. (This one is an issue close to my heart as it's almost certainly the reason why my employer has a 10% gap in pay between women and men - it's cock up, not conspiracy, but my pay packet is still even more derisory than that of my male colleagues).
Unless there is a business case as to why the job has to be full time, advertise all vacancies as open to part-timers/flexible working/ job shares.
Discourage a culture of presenteeism (which is counterproductive anyway - in most jobs, beyond 35 to 40 hours a week productivity per hour goes down, mistakes go up, and by about 45 to 50 hours, you're making so many mistakes you're getting less done than you would have on a shorter week). Don't make promotion/ performance pay/ bonuses depend on "number of hours your arse is on the seat"(which discriminates against anyone with caring responsibilities - predominantly women).
Barring jobs like travelling sales people, try to cut down on family-unfriendly work travel - how much of it can be done by phone/video conference? Don't make performance related pay dependent on going to the big meeting in London to schmooze if half your staff find it really difficult to have a night away from home.
Bring in clear and transparent criteria for pay rises - not amorphous words like "Bloggs shows flair in how he handles situations."
Make pay scales transparent so people know how much the rate for the job is and where they are relative to it.
Don't slice and dice job descriptions to try to make it hard to find direct comparators (e.g. have a job grade of "adminstrative assistant" rather than separate "soft people skills facilitator" and "technical advisor" which involve roughly the same amount of nous and deliver the same benefit to the firm, but magically the former is mostly women, who just happen to be paid less than the latter, who are magically mostly men...)