How can I clean out 'other' space on my Mac?

You "clean out" files by dragging them to the trash and emptying the trash.
"Other" is like "None of the above". Like "Please choose your ethnic group: White – Black – Other. Half the world's population is "Other".

Here is what IS NOT "Other"...
Photos and in the photos folder , music in the Music folder, documents in the documents folder –– Music and pictures not in the correct folders.

OS X can recognize music and pictures no matter where. There is no rule about the location. I don't want to retype a tenth time the full explanation, so please read one of my Best Answers about the mysterious "Other"....

>> http://answers.yahoo.com/question/index?qid=20130804134619AAvQpRM (Best Answer for “What is ‘other’?”)
>> https://answers.yahoo.com/question/index?qid=20140106162252AAjEPw8 (Best Answer for “What is ‘other’?”)
>> https://answers.yahoo.com/question/index?qid=20140201081833AAwUacn (Best Answer for “What is ‘other’?”)

If it helps any, I have over 480GB of "Other" on my internal storage, but that makes sense, because it is mostly AVI movies and OS X doesn't use that file type (Windows is losing it, too, since it never was much good).

other is basically anything saved by a program that the mac doesn't recognise. Photos and in the photos folder , music in the Music folder, docunts in the documents folder etc. If you have something like dropbox installed then the mac can't tell what the things in the dropbox folder are so just calls them other. If you have any games on your mac, any saved games will come under other. Music and pictures not in the correct folders come under other.

Clean Your Mac Easy!

clean out some cpu operating stuff on task bar

Use canned air to get the dust out.