You can edit or reply to any part of a wave by double clicking on it.
Submit and create new replies with 'Shift+Enter' to make a conversation go faster.
Give yourself a picture instead of a grey head. Click on your name in the Contacts panel.
Link to another wave
Create a link to another wave by dragging it over from the search panel while you're editing.
Share a wave with the world. Add firstname.lastname@example.org to your contacts, then to the wave.
Use the G+ gadget on the editing toolbar to add a link, image or video to your wave
Source : http://googlewave.blogspot.com/2010/02/ten-tips-for-waving.html