I read that NG article too, and I've been studying Buddhism for quite a while now. I've been trying to form my own conclusions about happiness - not sure how close I am yet, but I've experienced a few epiphanies in the search.
One of those epiphanies is this:
Happiness can come from others, but never taken from them (like respect). Therefore in my own quest to find happiness, it becomes imperative that I help as many others find their own happiness along the way. I have had several moments of enlightenment on this subject, and several times have been perfectly willing to do anything within my realm of capability to do, if it would truly make someone happy.
Ask yourself this: what would make you happy, and how can I help? No matter what the response is, consider if it's something you are able to do (without sacrificing your own happiness, but that in itself is a meditation to ponder). If the person needs fifty bucks to get something, then consider if you can spare the fifty dollars. If they need a hug, consider if you're willing to give them a hug (there are almost no cases where you shouldn't be capable of giving one). The point is, no matter what they say, consider if you can do it for them. If it's something you're not capable of doing, then tell them that. If you're not willing to do it, ask yourself why not, and really listen to the voice in your head - is it truly something you cannot do, or is it just something you don't want to do? Consider what would happen if you did it anyway.
Of course there is a lot of trust that goes into that sort of thing. If you really don't trust this person, then there is no law against turning them down. But with friends, family, and close ones, there should be no reason not to trust them, and therefore no reason not to do something for them, if you are in fact capable of doing it.
Another thing to ask yourself: Why is (whatever is making me unhappy) making me unhappy? More often than not I realize that it is not something that is making me upset - it is my reaction to it that is causing the emotions. I'll admit that I have a fair amount of road rage - people on the roads drive me crazy. But when I get cut off or someone doesn't use their turn signal to change lanes ... I get upset. Then I ask myself why is that making me upset? I'm not being made late for work, I'm not in any danger, and their actions really haven't affected me - I'm just reacting in a negative way, and that's making me upset. It's almost like I know it's supposed to make me upset so I let it. The key is to un-learn that behavior. We can't get upset at another person unless their actions remind us of something we don't like about ourselves. I believe Ghandi said that in order to forgive others, we must first learn to forgive ourselves.
So when you think about why you're feeling upset, sometimes you'll realize you're upset for no real reason. If the bills are keeping you up at night, just remind yourself that there's nothing to be upset about at that moment. There's nothing you can do to change the situation while you're trying to sleep, so don't let it bother you until you get up. There's a time and place for worrying about things, and it's not "all the time." Take a deep breath, push your cares away and just relax. It's easy when you realize that you have the power to relax at any given time. Take ten seconds and forget about everything. Waiting for ten seconds isn't going to make things any worse, after all.
And I'll stop there.