You’ve mastered the cable cross-over and amped up your push-up. Now it’s time to perfect your form on a set of skills that often get overlooked at the gym: your manners.

We spoke to author and etiquette expert Dan Post Senning (great-great-grandson of the original maven of manners, Emily Post!) and Ramona Braganza about what constitutes courteous—and crass—behavior at the gym.

IN THE LOCKER ROOM

Do: Towel It Up, Dude
Let’s just get right to the point. Not everyone is cool with nudity. Yes, the human form is a beautiful thing. And we get that you’re proud of the work you’ve done and the way your body looks. But given the semipublic nature of the gym locker room, save those hour-long looks in the mirror for your bedroom.

“You’re not there to be on display, or to preen and promenade about,” Senning says. “You have some liberties to be naked, to shower, to get dressed and undressed, but out of consideration for others, exercise a little bit of modesty.”

Don’t: Burn Through Your “Anytime” Minutes
This rule definitely applies to every area of the gym: Save the cell-phone conversations and marathon email sessions for outside the gym. Most people see the gym as a chance to tune out from telephones and email—so whether you’re running late to work after your early-morning workout or letting the kids know that you’re on your way home, keep your phone calls, text messages and emails short.

“The same rules apply as in a restaurant,” Senning says. “Out of respect for your fellow diners and the owners of the establishment, you wouldn’t carry on a conversation in the middle of the dining room floor, so don’t do so in the locker room.”

Do: Wash Your Hands
This might seem like a no-brainer for most folks, but a quick reminder never hurts: Clean hands are a must for anyone heading out to the gym floor to use cardio equipment or weight machines. (And just to be extra courteous and hygienic, wipe down those machines when you’re done using them.)

AT THE WEIGHT ROOM

Don’t: Create a Slip-n-Slide
Most people go to the gym with the express purpose to sweat, but do a favor for everyone queued up behind you at the bench and wipe down the area when you’re done.

Do: Keep the Noises to a Minimum
A small expression of exertion—a sigh or long breath—are perfectly acceptable; grunting, groaning, weights slamming and other Olympic-lifting noises are better suited for, well, the Olympics. If you’re planning to bench some scream-inducing weight, schedule your workout for an off-peak time.

Don’t: Offer a Tutorial
“As a trainer, it bugs me when people try to correct my form,” Braganza admits. “Whether they’re using it as a pickup line or trying to show off how much they know, it’s just rude to offer unsolicited advice.”

Of course, if someone is clearly attempting an unsafe movement or is on a crash course with injury, definitely offer a helping hand or alert a member of the gym staff.

Do: Get Help
Never be afraid to ask for advice or for a spot. If you don’t feel comfortable asking a fellow gym member, then look for a Gold’s Gym trainer.

Don’t: Double-Dip
Repeat after us: I can only use one machine at one time. Don’t try to reserve the hip sled by throwing a towel on it while you finish that set of lat pull downs or take a 10-minute break to chat with a buddy. We understand you want to get the most muscle burn in the shortest time, but there are other people who want to use the hip sled and the lat pull down.

Do: Ask to Share
Instead of tapping your foot and checking your watch over and over while you wait for the chest press, ask your fellow gym member if you can switch out sets. That said, if you can see that two people are already sharing a machine then just keep moving. Two is company, but three is a crowd.

ON THE CARDIO FLOOR

Do: Limit Your Screen Time
Sure, you get a little ego boost every time you whip out that iPad or Kindle, but be sure to watch the clock—or even set the alarm. When lines of members are waiting to use the machines, focus on your workout rather than on your epic Angry Birds battle.

“E-tablets have a tendency to draw people in so they lose awareness of the people and environment around them,” Senning says, meaning that those intense 20 minutes you planned to spend on the recumbent bike may stretch to a leisurely 45. Which brings up another point…

Don’t: Hog the Machines
Most gyms assign time limits to the machines, especially during peak hours. Pay attention to how long you’ve used a piece of equipment when other people are vying for a turn, and give someone else a chance when that time is up. “If you want to get in a 40-minute run at 6 p.m., switch cardio machines halfway through,” Braganza recommends.

Do: Share the Water Fountain
After a monster, water-bottle-emptying workout, you head to the fountain to refill your Nalgene when a parched yet water-bottle-less lad sidles up behind you. In this situation, Braganza offers this tip: Step aside and let the dude quickly quench his thirst before you spend five minutes commandeering the faucet. Hopefully, the next time you forget your water bottle at home, someone will return the favor.

Don’t: Forget the Deodorant
“The No. 1 rule of gym etiquette is to be clean,” Senning says. That means wearing deodorant and antiperspirant at all times, and putting on a fresh pair of clean clothes. The Emily Post Institute even recommends asking a person you trust to give you a quick sniff test every now and again. “Have them evaluate your breath, body odor and even hair—things you yourself may overlook sometimes,” Senning explains.

IN A GROUP FITNESS CLASS

Do: Leave the Front Row to the Pros
While everyone should try out new classes, nothing bursts Yoga Zen faster than a person who keeps falling out of a pose directly in your line of sight. Don’t ruin a Zumba routine for your fellow classmates by taking center stage on your first go-around.

“Stay near the instructor but to the far left or far right, so you’re not interrupting others’ concentration,” Braganza says.

Don’t: Make a Beeline for the Door
“What tends to happen is that people gather outside the door before the class begins, then when it’s time to enter, everyone bum-rushes the studio,” Braganza says. To avoid a stampede situation, hang back and let the pushy pushers go in first. It’s not like the class is going to start any earlier for them.

That said, if a certain fitness class is constantly overcrowded, talk to the gym staff about creating a sign-up sheet.