My battery last for about 2 hr. Everyone elses lasts all day.

Battery life obviously depends on what you're using it for. Watching video or streaming lots of data will run the battery down quickly but I'll assume you're not doing that.

If the iPod was new, the batterie's defective and Apple will replace it, but it sounds like you got it used. You're best bet is to replace the battery.

Batteries wear out. Apple has some pretty comprehensive battery care instructions that I've found very useful but batteries will wear out eventually no matter what.