"She doesn't look like a gamer"
That was something I saw said in Gamespot's Twitch chat last week. To me that quote just seems kind of absurd, as if females that play games must look a certain way and anything else must be treated with suspicion. Anytime the issue of sexism gets brought up on a lot of games sites (like this one), some of the comments get pretty terrible.
It's hard to say how it got as bad as it is and there is far more to say than I could possibly do so in any reasonable amount of time, so instead I'm just going to try to just talk about a couple of specific things.

Within the gaming communities themselves there need to be mechanisms in place to prevent abuse being hurled across voice chat and people just abusing the communication tools that each of the platforms offer. XBL has been the prime example of this but it's hardly isolated to just there. And I think it goes beyond anonymity and usernames, I think something like that would see some improvement but there are plenty of sites that do have good communities that allow for only online handles.
The suggestion of lifetime bans doesn't sound too terrible, it would give some sort of consequence for one's actions. That wouldn't stop them from making a new account (you could disable it at a console level, but there are problems with that when it comes to people buying second hand) but given how much gets tied to those accounts now, achievements, DLC downloadable games it would definitely be a consequence to being abusive on a given platform. While you could make an argument that it might be a bit harsh a punishment, I think that it should at least be a potential tool to be used.
In the less controversial tools that platform holders could use they could put in just easier tools to mute certain players. If a certain person is getting muted by every player they come across they should probably just start off games muted by default. Just taking away their megaphone would do a great deal to improve just the overall environment in online games. There is something to be said for trying to promote people not being jerks in your communities, but I don't really have any ideas on that particular front.
Now onto the actual game side of things, women are remarkably poorly represented in games. That's not to say there aren't female characters, but there's a remarkable lack of diversity amongst those characters and only a small handful of them are actually strong characters. More often than not they're throwaway characters designed as a plot device, scenery or just as a sexual object.
An individual instance of any of this stuff wouldn't be so terrible by themselves but the fact that they are far and away the majority of what we have is really quite bad. As a whole we have managed to create a whole bunch of female characters that are little more than objects for sexual fantasy, from skimpy outfits to completely over sexualised body images. Yes there are unrealistically proportioned male characters as well, but there exists the diversity of what a male character can look like and also they aren't made to look that way for the purposes of sexual fantasy but power fantasy.

This in turn makes a lot of games just much less appealing to a lot of women. When you have characters that are little more than walking breasts, it's not hard to figure out why they aren't characters people identify with or memorable. Think about the most memorable female characters in games, Samus and Alyx Vance immediately come to mind along with a handful of others. They were full characters in and of themselves and that's what makes them awesome. But there aren't enough of them, women make up half the population on the planet we should be doing better than this.
I suspect that a lot of this has to do with the fact that the majority of game creators happen to be male. Here in the UK the last I heard we have a massive 12% of game developers being women. That's fairly significantly down from many years ago, but that's still pretty bad no matter how you look at it. I think we should be having a larger influx of new game developers coming out soon through newer games courses so that should give some push but I'm not holding my breath for something drastic.
Part of getting more women in games development is just getting more women to be more active in games and games communities. That doesn't mean that we need to start making games specifically for women, in fact that philosophy has frequently backfired for just making utter rubbish. But by making the games less exclusionary in nature and by increasing the diversity in the games that we make. If developers keep making nothing but male power fantasy games we're in for a pretty big uphill battle.
So just a last open letter to game makers, don't make the pandering BS that so frequently gets put into games. I get that it sells, but it's cheap. Your game might be great, despite your skimpy female armour that protects exactly zero vital organs. It wouldn't be the first time and it almost certainly won't be the last. We can do better than that and yes there is sexist behaviour and themes in other media, but just because that's true doesn't mean that we can't do just a little bit to make our little corner better.