As noted before, you can safely delete the GarageBand Apple Loops folder and iDVD themes from a standard OS X install if you don't need them. Deleting duplicate or unwanted tracks from iTunes is also a great space saver and clearing out obsolete photos from iPhoto will help with the clutter.
The Find function in OS X can be helpful here, as it lets you search using multiple criteria. So, for example, you could search for all items over 50MB in size that were last opened over one year ago, or something similar.
This would give you a list of items matching those criteria, which may well reveal large files or folders that you had forgotten about or lost. At that point you could decide to back them up or delete them altogether.
Slim the startup items
Startup items are another area where you can trim some fat. Some programs on installation place a startup item into your account so that a program or a helper starts up on login.
The worst culprits are printers and scanners, which tend to put clumsy and slow assistant programs in to load automatically, which slow down your login and without which the peripheral will almost always work perfectly. Go to System Preferences > Accounts > Login Items and delete any errant ones. You're unlikely to break anything by doing this.
Similarly, some installers add preference panes to System Preferences, generally to be found in the Other section. If these are no longer needed, right-click or [Ctrl]-click on them and choose Remove…, and they will be sent to the Trash. Similarly when you install widgets it can be easy to let them build up and forget the ones you never use.
To clear them out, open Widget Manager and you'll see a red symbol next to each one that can be deleted. Clicking this will send it to the Trash.
How to remove unwanted languages with Monolingual
1. Download and open Monolingual from the disc. Be very careful: if you're not confident with the process of stripping languages out of the system, stop now. If you are confident, then make sure the languages ticked are the ones you'll probably never use. Make sure that you don't click your native language.
2. Click Remove and the program will warn you that the step you're about to take cannot be undone without reinstalling the whole of OS X. Take this warning seriously. If you choose to continue, it will search the many localised files present on the system and inside applications and delete the ones you have specified.
3. The second tab is Input Menu, and here you can remove alternatives like Chinese and Korean; this won't reclaim a huge amount of space. Architectures can strip code from applications based on the code's CPU framework. This is best avoided; if you make a wrong move you could damage your system, necessitating a total reinstall.
First published in MacFormat, Issue 202