Now that we're back in the mode of having a new release fairly frequently we need to set a few guidelines on how to post a bug report to make it easier for Toady to fix things.
Here's the things definitely needed:
1) VERSION NUMBER!! This is the MOST IMPORTANT. As I was looking at the bug forum and the recent dev news, I realized that it's pretty difficult for Toady to discern which bugs were new vs old. Posting date doesn't count cause people may be using older versions.
2) Screenshots or movies can explain things a lot better than simple text. If it is possible to see it, please let others see it as well. PLEASE NOTE: the PRINTSCREEN key is great and all, but we don't need to see your whole desktop, and frankly it sucks to remove everything but the DF window (if it is windowed of course) in your favorite image editor. ALT+PRINTSCREEN will take a screenshot of the currently focused window only!
3) Is it repeatable? I know having a crash sucks, but this is an ALPHA after all. So if you get a bug, don't be discouraged and try to get it to happen again. If you get into the mode of doing this, even bug-hunting can be worthwhile since you know you're helping the community. As a side-note, be on the lookout for odd things too!
4) And finally, if you could provide a short text description in addition to a picture, definitely do so! Although pics are great, sometimes it's also easier to talk about what you were doing at the time of the bug: events leading up to it and such.
Also, some things to consider:
1) Whether you are using any mods, or not. If you start having problems, try removing any mods (even graphics) before posting a bug. Most modders already know this, but it needs to be repeated. DF is very mod-friendly, so by all means, mod the **** out of it. But if you start to have problems afterwards, see if it is the mod's problem and report it to the mod's writer.
2) Did you do a clean install? If not, try removing your data folders and generating a new world.
3) Are you using a pre-generated world? If so, did the original owner use any mods? Also, remember that version changes may invalidate pre-generated worlds.
4) Did you check the list of already reported bugs? If so, does it say the bug is repeatable? If you can find a way to make it repeatable, let us know!
This is just my opinion on what is needed for a bug report. If you can think of anything else that is important, feel free to add to this list.