It's not an art, just a skill, and takes some practice.

Keep trying, fill the gaps with casual conversation and no one will notice.
You're on a sunny piazza - music, flavours and flowing conversation - feeling blissfully Italian - until a steaming plate of spaghetti alla carbonara is placed before you and panic sets in, where's the knife?
Tranquillo, you don't need a knife, follow this simple guide and learn to twirl like a pro.
Practice makes perfect, order spaghetti daily until you've got the knack, this is our sage advice.
The trick is in the choosing.
One needs to be decisive, right from the start
Pick up that fork like you own it.
Glance at your plate and choose 2 or 3 spaghetti, no more. The ones on the edge are easier to twirl using your plate as a backdrop (and yes, spaghetti is plural).
Slide the chosen spaghetti onto your fork and lift.
With a continuous scooping and twirling motion, use your plate to keep them on your fork until they're all twirled up
Here's a handy little video featuring spaghetti with pumpkin, Speck, walnuts and gorgonzola.
Grazie, prego and buon appetito!
Tips:
If it's going wrong, don't be tempted to shove the entire untidy forkful into your mouth and hope for the best. Abandon ship and try again. With sauce on your face, and hamster-cheeks, you might end up choking, plus, bitten-off strands of spaghetti falling back onto your plate aren't fantastico. Slide the deliciously messy ensemble off your fork and start again, skip to point 1.
Remember, you can always use a spoon, you just can't use a knife to cut spaghetti, it's an unsaid, nationwide rule.
Use said spoon in your other hand as a base for twirling and if there isn't a spoon, you can ask. No knowledge of Italian is required, just gesture 'using a spoon' and your waiter will understand with a quick nod.
Ask for a knife and a subtle display of horror, rolling of the eyes, hand gestures and a quiet obscenity is what you'll get (along with the knife), depending on your waiter of course.
Do not fear my friend, you can do this. Take your sweet time - in the end, you'll savour your beautiful food eating slowly and loving every spaghetto.
Remember to fare scarpetta with your bread (it's already on the table) and mop up every bit of sauce on your plate. Now you can sit back with a contented sigh and think about an espresso.
Bravissimo.