I believe that it's easier after the first time, simply because you know what it feels like, and what to expect, at least to some degree.

That doesn't mean that it suddenly becomes ridiculously simple, or that you'll start having LDs every night after that first breakthrough. But I definitely think that it should become easier -- I know that after I had my first "induced" LD, it was easier to repeat the trick than it was to make it happen the first time.