First thing I did: tried to reject those floating stuff like VB.NET that was in fashion 3 or 4 years, C# (that is changing constantly and you will never be good enough) and in general - reject everything, that has a lifespan shorter than 10 years, so you have the time to master it.
In my case, I started looking for another job: python instead of .NET and linux administration/scripting instead of regular developer. I cant imagine in several years being one of those amazing old geeks, staring at Visual Studio or Excel macros. Come on, old geek must be a master of console and all those youngsters around must be astonished and charmed by your skill and magic. You will never beat them in .NET 8.5 RC2 just because it will be completely different than today's .NET
Long story short: Im trying to master the things, that have i.e. books released 7 years ago and they are still valid.