Most applications use ⌘+m to minimize a window.
As for your question about a keyboard shortcut for zooming a window, there is some discussion here:
http://www.macosxhints.com/article.php?story=20051227001809626
I think the most straightforward solution is to type the following in the terminal:
defaults write NSGlobalDomain NSUserKeyEquivalents '{"Zoom" = "@^Z"; "Zoom Window" = "@^Z"; }'
Most applications have a "Zoom" or "Zoom Window" menu option (usually in a Window menu) — the above command sets the default keyboard shortcut for that to ⌘+control+z
Another handy shortcut: when you really get in trouble and an application is non-responsive, ⌘+option+esc will open the Force Quit Applications dialog.