Most of the times I was sent a notice for jury duty I happened to be in college and used that as my excuse. It is a very good excuse, by the way. They won't make you show up when you write them a letter saying you are several hundred miles away attending a university.
I only had to sit through jury selection once so far and it seemed pretty easy to get excused. Either the lawyers weren't very good in the case I was being selected for, or all lawyers think ordinary citizens are morons. Because, it was as if the lawyers weren't even trying to hide the motives behind their questions. And it was obvious which answers they didn't want. So if you really want out of jury duty, just pay attention to what the lawyers ask and give them the answers you can tell they won't like. You don't even have to go on public record saying bad things.
The case I was being selected for was one in which a man had hurt his wife. Some details about how the case was going to be argued were obvious from the lawyer's questions. The man's wife wasn't interested in having her husband prosecuted. The DA had to prosecute anyways due to the nature of the crime. The man's defense would be that his wife was suicidal and she got some minor injuries from what he did to stop her; and since he had good intentions and she still wanted to work things out with him it didn't seem right for him to be prosecuted. The DA was going to argue that you can never, under any circumstances, hurt another person.
First the DA asked if anyone in the jury thought there was ever a good justification for hurting someone. That was the first opportunity to get out, but it seemed like a bad way to go on record. Then the DA asked if anyone was bothered by the wife's reluctance to see her husband prosecuted. I jumped on that one and got myself excused. I just said, "Yeah, that seems rather interesting to me. I'd be real curious as to why the court is going against the victim's wishes." I got excused immediately for that.