I have several project files containing different arrangements of the same song, I’d like to be able to open 2 different projects side by side, and then take audio/midi clips from one and copy them easily to the other.
Can anyone advise on the easiest way to do this?
Is it simply a copy/paste job, or do I need to use library features? (I’ve not used these before)
There may be an easier way (and I’m sure someone will chime in if there is) but, my workflow is to export the track file(s) to the desktop then import those file(s) from the desktop location into the “other” project. Making sure it puts a copy into the “other” project file (pool). This way I am assured that the files are independent of each other (meaning not shared).
Regards 
I really like the Import Tracks from Project option. I usually use it to bring in vstis and audio track settings from totally different productions, but it will work well for you in this context.
I wasn’t familiar with those options, I’ll check them out thanks!