If you don't already, make sure you wear earplugs when your gigging, rehearsing or going to a gig!
At the moment, at least in the UK, if you are part of the Musicians Union you can get a free hearing test and moulded ear plugs for around £60. If you can spare the cash, getting moulded ear plugs are the way to go. Either through the MU or any company that provides IEM's will more than likely have an ear plug option too. At the moment I use moulds from a company called Read Audio based in the UK.
If you can't spare the cash there are great cheap options out there. At the moment I keep a set of Thunderplugs on my keys, this means I'm not taking my moulds everywhere, they cost £9.99 and are a great little set. Another option are Doc's Pro Plugs, about the same price and generally just take allot of edge of the higher end.
If you have never used ear plugs before, they can take some getting used to, but it is totally worth it. One way to try to get used to them is putting them in as soon as you arrive somewhere and leave them in the whole time. It might make talking to people a little odd, but afterwards you'll feel great for not having any ringing in your ears!
If anyone has any recommendations of moulded companies or good cheaper options, share the love!