Over the last couple of years I’ve been mostly a Mac user, well as far as the desktop goes, it’s been Mac. On the server side its been some flavor of Unix. So I’ve come to appreciate the Mac OSX operating system quite a bit, I think it’s beautiful and love the history going way back to BSD 4.4, in proper Unix fashion. And I’ve also found some useful things that help me get around. This might help you as a newbie as well, assuming you’re coming from Windows or Linux. I know this has been done already a dozen times out there but I’m doing it anyway.
Here’s what I use nearly everyday on my Mac and could not function as well without:
Right click
Even with the one button looking Mac mouse you can still configure it to right click. If you have a really old Mac mouse that only has one button then grab any old two button USB mouse.

Apple Menu -> System Preferences -> Keyboard and Mouse -> Mouse -> Choose Secondary Button for right mouse button
Use iChat
iChat supports a couple protocols, mainly AIM, Bonjour and Jabber. This is all I need thanks god. Bonjour allows you to see anyone else running on your local network without any configuration. If you use gmail and gchat you can configure your iChat to login with your google account and provide the same functionality as gchat but integrates with your desktop better. In other words, you can sign out of gchat all to together, no annoying sounds or blinking tabs anymore.
Running your google chat in iChat still saves them in your google account because they are still going through jabber and google’s servers. I also like to save the iChat chats to my local file system as well so Spotlight and Finder are more useful. I also increase the font. You can do this stuff in preferences, iChat -> Preferences -> Messages.

Monitor you system with iStat

http://islayer.com/apps/istatmenus/
Download and install this, then configure it in Apple Menu -> System Preferences. You need to know what your computer is doing.
Finder
Use Search For
Finder gives you some very useful things in the left column that I often overlook. Namely the section labeled “Search For”. Here you can find almost any document or chat that you did today, yesterday, or this week.You configure that sidebar in Finder -> Preferences -> Sidebar

See your filename suffixes
Most people I know are used to seeing their filename extensions, that is a preference in Finder. SeeFinder -> Preferences.

Keyboard shortcuts
Cmd + Tab
Cycles between applications.
Cmd + Downhill Quote (under the escape key)
Cycles between windows in an application.
Cmd + Space
Starts spotlight
Cmd + Shift + 4
Screenshot with crosshairs. You can select something with the crosshairs or you can press the space bar and it will highlight the entire application window, then click the mouse to capture it. All screenshots end up on the Desktop in png format labeled Picture [number].png.
Cmd + Shift + 3
Full screenshot. Not as useful as its older brother but still useful.
Cmd + Right/Left/Up/Down Arrow
Skips to the end/beginning/top/bottom of a line or text area.
Cmd + z
Undo
Cmd + shift + z
Redo
Remember you can undo and redo multiple times, but this doesn’t apply to mouse clicks like saved preferences but almost anywhere in an application where you are typing or moving things around.
Cmd + l (ell)
Go to the location bar in your browser. Then tab goes to the search box.
Cmd + a
Select all text. Anywhere you see a text field, could be your browser location bar or a word document, cmd+a is your friend.
Cmd + =/-
Using the = and - keys in combination with the cmd key allows you to zoom your browser window. I do this all the time because otherwise I would be squinting.
Customize your dock
The little tray of applications at the bottom of the screen is customizable. You can pull and put stuff in it by drag and drop and you can adjust the size and magnification values in Apple -> Dock -> Dock Preferences. I suggest removing stuff from the dock that you don’t use often so there is less to hunt and peck from. When you want to launch a new application that is not there use spotlight Cmd + space and type to find the app or do it the old fashioed way and launch Finder.
Change default folder for screen captures
If you’re like me, debugging apps and explaining screens and such, you are taking plenty of screenshots or screen captures. On macs these generally end up on you Desktop and can quickly lead to clutter. Luckily there is a way to specify what folder they go into. On Snow Leopard, for example, I ran these commands in Terminal after creating the directory:
defaults write com.apple.screencapture /Users/mandric/Desktop/Screenshots killall SystemUIServer
Firefox
Tell Firefox to put stuff into your Downloads folder, not your Desktop. This helps to keep your Desktop nice and clean and when you need to take out the trash you know where to look.

Fluid + Gmail
Want to get your gmail out of the browser and make it more integrated into your desktop workflow, like a regular app? Fluid is for you.
- Download the .app file and then move it to your Applications directory and launch it.
- Enter http://mail.google.com/ into the homepage URL.
I had a problem with the icon, for some reason I had to set it manually in the General Preferences. I found a nice one thanks to Chris Ivarison. Scroll to the bottom for the gmail icon.
There was also one tweak I did, here’s my preference pane where I checked the box so closing the last window does not exit the application.
