A group of my local (Boise) geek friends have been using Google Wave to share Google Wave tips and tricks with one another was we each kick Wave’s tires. Here are some of the most useful tips/tricks that have come out of that ongoing conversation:
1. The “Files” button 
in the lower right doesn’t work unless someone has already uploaded a file. The “Files” button is not used to upload files (yes, very illogical). To upload a file, you need to click on the paperclip icon. Note: you can’t see the paperclip icon until after you start a new reply or are otherwise in “edit mode.”
2. If you add an image (Tip 1 above), a separate button for Images shows up next to the Files button. Perhaps the Files button shouldn’t be visible until after there is at least one file…
3. The first line of the first message (aka “blip”) you type in a wave…becomes the title of the wave. Having a nonsensical wave title is frustrating when you are looking for a wave amongst a list of waves. Yes, you can go back and edit the first blip to make a better title.
4. In a “wave” you’ll have a number of threaded conversations. Each conversation is a “wavelet.” Each message in a wavelet is a “blip.” See this Mashable post for a more thorough explanation.
5. If you push the “Reply” button in the upper toolbar, you start a new wavelet. 
.
6. If you mouse over the bottom of a wavelet window that no one else has responded to, you receive the option of “Continue this thread.”
7. If you mouse over the junction between the two blips in the wavelet, you receive the option of “insert reply here.”
8. If you double click in the middle of a blip you can insert an inline reply.
I’m sure those tips are just the tip of the iceberg…
Update: A video worth watching:
