It all depends on what you mean by self-improvement:
Do you want to be better at competing in the market place, or do you want to be a truly "good" person (the kind that brings joy into others lives without being a pain in the neck and without hope of reward or favour)?
The first "want" is okay - we're all in the rat race one way or another, and if you have to work to keep body and soul together, then you may as well maximise your "earnings over free time" equation to whichever level suits you best.
But if you want true personal advancement, then the second, "saintly" path is the only one worth following.
Now, I'm no saint! And I don't always (never)practice what I preach. I easily get bogged down in the day to day problems of work and relationship difficulties, focus too much on money and how to make more of it, etc etc. Like everyone else.
But in earlier and simpler times, I did once attempt a constant "active love" for my fellow beings. I kept it from everyone and anyone, did not proclaim any particular set of beliefs (a hotch-potch of karma and inter-connectedness), maintained a "normal" outward persona, kept working hard just as before, kept on eye on my pension fund, went shopping, all the usual stuff!
But, at the same time, I attempted to project a generally benign attitude, forgave people their faults by refusing to see fault and by accepting my own imperfection, etc, and the results - completely unlooked for - were astounding!
So astounding that I found it all a bit frightening; things started going my way, people couldn't do enough for me and they seemed happier, work improved and became easier, wage rises galore, sexual interest from others hit an all time high, I lost excess weight, it was easier to get up in the morning, TV had never been so good - in short, everything improved....
So much so that I began to suspect that I had made a pact with a devil! In the end, I even began to think that I was in danger of manipulating people and circumstances for material gain, which was way off my original intentions, which was just to be a bit better as a person (less selfish, more helpful, that sort of thing).
So, I stopped doing it. I was also afraid (despite my "jokey" interpretation of sinister pacts) that now I'd embarked on this path, there was no turning back, and being a miserable, grasping, intolerant old git was a pleasure never to be known again!
But, before I'm due to shuffle off this mortal coil, I intend to give it another try, for it's own sake, not gain - if I've not disqualified myself from success by telling the world through this message the selfish gains I made (does "23 replies" in a discussion forum constitute the world?)!
NLP? Yeh, go for it, but don't get too wrapped up in what is a very useful technique, when there are more powerful forces at work in the world than the human intellect (ie love). For a wonderful, moving, in depth, but open-ended (in other words, make up your own mind - is sprituality real, or imaginary?) description of a young person embarking on the path of sprituality, and the paradoxes and trials thereof, read "Christ Recrucified" by Nikos Kazantzakis.
It makes a great read, whatever your views, and does not require that you come down on either side (sprituality or worldliness). But as a description of the human condition, moral and physical courage, truth, faith, and the life and times of ordinary people in war-riven times, it can't be beaten!