Women being paid the same salary as men that are doing the same work. I learned the hard way that the only way to ensure you are being paid fairly is to demand it. I think ultimately we should just make salaries or salary ranges publicly available.
Nothing (yet). I think it takes a long time to be considered an 'expert' and I've only been professionally programming for 7 years. I have extensive experience in Angular (1 and 2+), SQL, Java and AWS.
Share your salary if you feel comfortable doing so. If you notice someone having a hard time getting a word in during a meeting, speak up and address them directly so they have a clear chance to speak. Ask their opinion about all the things. If they have helped you out, thank them. Mostly, just be kind.