Old style whistle....keep on a lanyard around your neck, it helps much better than the pathetic duck call horn of a moped.
>>if you have a backlog of traffic behind you, carefully edge over to the right to help pass you in a safer manner.<<
I reccommend against this...too easy to be trapped into 2 feet of space and faced with an upcoming pothole or (worse!) old-style sewer drain...and those are deadly to a moped.
Make a right turn and get off the road, take a short break or something, pull into a gas station...it's hella safer.
Oddball bit - have a martial arts instructor teach you how to do a breakfall roll, or "four point shoulder roll"...it's well worth the time and money.
Reason is, if you should happen to part ways with your wheels, as can happen in a front wheel jackknife (front wheel catches curb and snaps sideways)...it IS possible to go flying over the bars at 30mph, and not take any damage if you know how to properly rollout and break the fall...you can't do this from a motorcycle, mind, but you CAN do it from a moped, I've done so more than once.
Handling a flat - rear tire.
Do NOT manuver - let off the gas, do NOT hit the brakes, or if you must , tap the front brake verrrry gently, but don't dare touch the rear...keep it straight and steady, and let the speed roll off, and dismount and get it off the road - if you try to turn, in any way...with a flat rear tire she'll slide out from under you like butter on a pancake griddle.
If you need to slow down fast, hit the kill switch, but remember that dumping that much speed with a flat can cause a little slide.
Handling a flat - front tire.
Same basic principles, but apply rear brakes, and you can apply them a bit stronger, most of your weight is to the rear, so this one isn't quite as dangerous, although you would think it would be the other way around.
Handling a skid.
Mopeds don't generally skid, unless you drive like I do, and in that case - the only skid you are likely to face is a rear-wheel skid from overcornering.
Immediately get your opposite leg down and let off the throttle, while throwing as much of your weight as you can to the OTHER side of the frame, this will yank the moped back upright and hopefully restore traction...and the much lighter weight of a moped allows you to "muscle" it, a trick not known or useable on motorcycles.
I would practice this a bit in the driveway, but safer to simply not overcorner, this is a just-in-case bit here.
Crash stop aka "45-slide".
This is also a moped-only trick, although I have seen it done with motorcycles by the insanely brave.
Reserve this for occasions most dire, but remember it, some day you might need it.
Basically you slam your left leg down and drag the heel as you lock up both brakes solid and lean in behind your moped, putting the entirely of it's weight and mass between you and what you are about to hit.
Properly done, the moped should be at a 45 degree angle to your original travel direction once the brakes lock.
What this does, is put maximum rubber to the road and an otherwise impossible amount of friction and braking power at your use - but it also puts the entirety of your moped between you and what you are about to hit...the moped is more replacable/repairable than you are, and if you do impact something, you are far less likely to sustain dire injury -because the moped itself becomes your "crumple zone".
Again, save for occasions most dire, but keep in mind...this trick's saved my ass many a time.