The "tip" I use most often is one that will save you from having to touch that pesky mouse so often: Alt + 1
Alt + 1 will place focus into the command window so that you can actually type a command and so that up-arrow actually scrolls through command history. However, it doesn't work if your focus is already in the scrollable command history.
Peeve: why the heck are key presses ignored while the focus is in a source window? It's not like you can edit the source code from inside WinDbg. Alt + 1 to the rescue.
