Visual modeling relies more heavily on the mouse as an input device than traditional (textual) programming. Still, the keyboard can be used in many places as an efficient replacement for a mouse click. Here are some examples.
Confirming a form with an OK button can be done by pressing Enter. However, if you are editing text in a multi-line text box (e.g. a microflow expression) Enter inserts a new line. In those cases you can press Ctrl+Enter to apply changes and exit the form. The Escape key closes the form without saving the changes.
If the keyboard focus is on a grid of items, for example the attributes of an entity, you can create a new item with Ctrl+N, edit an existing with Enter and delete one with the Delete key. The arrow keys can, of course, be used to move the selection up and down.
Finally, when building forms the keyboard shortcuts Ctrl+Left and Ctrl+Right move things to the left and right. You can move buttons, columns, search fields and tab pages in this way. This is much faster than by using the mouse.
Look forward to a lot more keyboard friendliness in the Modeler in 2012!