sustain

Well, the way to make a real guitar sustain is to hold out the tone longer (and if it's electric, use an amp or amp model that allows for long sustain). And mind that the region must be long enough to allow for the sustained tone to be played fully.

I usually have excellent sustain - Get a Les Paul! What pickups are in your Ax? Humbuckers really have great sustain & sound great IMO - more so than single coils (like my Strat).

Steve Hadeen wrote:
Any tips/hints on how to make real instruments, especially guitars, have more sustain instead of just an abrupt end as always is the case for loops, it seems? ... I'm thinking of a final chord being played at the end of a song and letting it ring out.

Are you talking about real instrument loops, or real guitars getting sustain? If you're talking about adding an end-of-song sustain to a loop (which is what it sounds like to me), try this:

1. With the loop selected (bright purple) and the track editor window open, make sure your view is very fine--drag the slider all the way to the right so that you can see 32nds and 64ths.
2. Place the red progress bar 1/32 or 1/64 before the end of the loop, and press command-T. This splits the region where the bar is.
3. You can now pull that 1/32 or 1/64 to repeat it as you would any full-size loop. This will essentially repeat the last smidgeon of sound from that loop for as long as you want it held. Combined with a track-volume fade-out, it just might sound like sustain.

I have never tried the above, so it may fail spectacularly. Your best bet for real guitar sustain remains getting a real guitar, not playing with Apple's loops.

my bad... I thought you were using an actual guitar. I don't do software guitars 😉