I'm quite glad that this time I saw this question just as it opened, instead of at the tail end, once the deadline for submission has closed. I'm talking about the Bi-Weekly Question by 
Enjoying Each Moment for What It Is
This one sounds totally intuitive, but it's really not. Of course, if you're at a party, celebrating it is the most obvious thing. And yes, you could say you're celebrating life at the same time. Easy peasy. But what about other times, when the world around you is not celebrating? What if you find yourself waiting in line for hours, getting bored, or even worse, in midst a struggle? Can you still celebrate life in those moments? I'd say yes, and in fact, I would consider those the real important moments to celebrate.
After all, we are still alive in those moments, so it's a good idea to appreciate our existence. Maybe you can get involved in some human interaction why you're waiting. It'll make time pass more easily, and in the end you'll be one experience richer. As for times of struggle, it's probably even more important to realize all the things we can do while our blood is pumping through our veins. In fact, keeping our being alive in perspective may actually help us get through our struggle, and maybe even help us emerge victoriously. We may not be fighting for our life when we're arguing at the bank about a wrongfully charged transaction, but simply reminding ourselves that we are indeed alive may give us the necessary edge in attitude to turn things in our favor.
Challenging Ourselves
Of course I'm not saying that we should seek out confrontation on purpose. Though even that can have a positive effect, as the film Fight Club illustrates so well. But to each their own. In my own case, I love imposing ... hmmm ... let's call it reasonable hardship on myself, only to make myself more alive. One such way is going on a week-long fast, as I described in these posts. Granted, during the fast you are just dreaming about the celebratory feasting that we be otherwise used to. But just as the word "used to" implies, after a while the most delicious things lose their extraordinary tastes if you have too much of it. I can guarantee, though, that after a week's fast a simple apple is going to create an incredible celebration of tastes in your mouth. It's certainly worth trying.
Another similar way I learned to enjoy being alive is by using my body. Hiking, swimming, and bicycling are wonderful ways of doing so. Especially if you combine these activities with other self-rewarding things, such as outings in nature, and spending time with loved ones, getting tired becomes actually something to look forward to. Reaching a mountain top with friends might be the most stereotypical illustration for this, but it's always true: so worth it. Even getting caught in a hailstorm, suffering through a few hours of prolonged rain may make the hot drink / shower afterwards so much more delicious. If you do this every day for a few months, like I did on this magnificent trip, you understand how one can get addicted to it.
Of course all the hard times are literally no fun if there are no good times to look forward to. In a way the two depend on each other. Likewise, if life was simply smooth sailing all the time it would be probably just as bad. So the idea is to alternate them, hopefully without reaching extremes either way. Since we are not the only ones in control, it may happen that we find ourselves too much on one side, or the other. In that case we should simply appreciate the moment for what it is, and be aware that change is always inevitable.