Quick tip on a fantastic feature I just found out about in Logic 9 and above:

I often will create new versions of songs as I produce them, as a means to backup in case I royally screw something up. Usually something along the lines of "song-name-4a", "song-name-4b", etc.

A few days ago I sat down to work on a song I've been plugging away at for a while. I got about an hour into it, and had made a ton of changes, before I realized that I was working on an older version of the song. This meant the version I was working on was missing a bunch of edits and EQ tweaks I had done. I really didn't want to do it again, it would have slowed me down quite a bit. After some frenetic searching I discovered that there's a "Merge" feature in Logic 9 and above that lets you select another project file, and import only the tracks you want from it into the currently open project. You can even import in all of the automation, effects, and buses associated with the tracks. I was able to import everything in and after a little cleanup I had a perfect merge of the two versions.

All you have to do is open up the Browser, select the project file, and hit Import to get the track options.

Once you're there it's a question of selecting which tracks, buses, and effects you want. Import them, and boom! You're in good shape. Such a huge time saver.