I've written about service before in pieces of various posts. Service keeps the University running, and is essential to a functional department. However, the service load is distributed incredibly unevenly, which is a source of angst and frustration. I am the kind of person who likes to do a good job at the things I do, so I do put in quite a bit of effort in my service. This means I get asked for "favors" a lot. At this point, I've spent enough years at ProdigalU that I actually have (and can articulate) a service strategy that works for me.
1. Ignore the service slackers as best as you can
It is a truism that some people blow off service without any penalty, thus carving out more research time for themselves. This is incredibly and maddeningly frustrating to those of us who try to do a good job on service and STILL have the same sorts of research and teaching time pressures. This is exactly the same thing as those who blow off teaching (though we have very few of those in my department, to be honest), and I try my very best to ignore these facts as much as possible in my day to day life.
It is worth talking up your service contributions when merit raises are being considered. It is also worth bringing up service contributions when being asked for yet another "favor" from the Chair/Dean/whoever. Otherwise, I find that getting worked up about the unfairness of the service load is like getting worked up about the unfairness of life--yes, it is true, but getting frustrated and unhappy about it just hurts me and makes me more stressed out.
2. Try to pick up service obligations that you at least find interesting
No one really enjoys committee work, but it is much easier and more enjoyable to do committee work that 1) leads somewhere and 2) is at least somewhat interesting. I have enough years here to know which committees at the department level meet and do nothing vs. those that don't meet and do nothing vs. those that meet and get something done. I try to make all of my service tasks fall into categories 2 and 3.
Currently, my main service task does require a fair amount of effort, but it is vital to the department, and I can see the fruits of my labors pretty easily. I also enjoy the topic, and find it an interesting exercise. I don't really mind doing this sort of task, because it doesn't feel like wasting time. After my sabbatical, I asked to return to this position, because I would rather do service like this than many other possible options.
3. Since most people care about the department, but don't want to do the work themselves, they will follow your lead if you have a strong vision and can articulate it reasonably well
This is related to my point 2. One of the reasons I like my main service task is because it has a real impact on the department. In the course of doing my service tasks, I found that if I had an idea I wanted to implement, it was pretty easy to get people on board if I could explain the details clearly, concisely, and enthusiastically. Most people are aware when something is not working well, but don't necessarily want to solve the problem themselves. If you can give them a potential solution to back, most people are willing to give it a shot. This makes my work more enjoyable, since I know that my effort will go somewhere, and even better, that it is in the direction I think is best. As a result of my service position now (which concerns a topic I care about), I have an outsize say in some aspects of how our department works.
4. Saying yes to easy and/or interesting tasks helps you say no later to onerous or crazy-making ones
You have to say yes some of the time. You may as well say yes (or even volunteer) for some easy stuff, so that you can say with all honesty that you have a pretty full service load when future unpleasant tasks crop up. The last minute assignments are usually to difficult or frustrating things. May as well agree earlier to easier stuff.
5. People (even service slackers) do notice when you do service, so make sure they don't take advantage of you!
This may not be to your benefit (since it means people know who to ask for "favors"), but it is true. Everyone knows who the slackers are, even if there is no real penalty for being one. Having a reputation for doing the things you commit to and for getting things done is a good thing, even if there are no immediate rewards. That said, it is definitely possible to be taken advantage of. It is definitely possible to overdo it, and it took me a while to figure out when and how to say no. I think I am at a reasonable balance now, where I do enough useful service to keep things going (and feel like I am doing my part) without it being a major drain on my time.