My strategy is to think of a name so unique that no one else would think of using it. The one on my HN account I originally cooked up in Nov. 2014, and I never had to extend it with numbers to get it accepted on various forums (yes, most of them were fine with changing the nick). My biggest gripe is that since YT changed their username system in October of that year, my most popular channel is stuck on an old username despite being a few months older.