Put everything back where it belongs

This might be the number-one gym etiquette rule. Don't leave a trail of equipment behind you: If you use something, put it back. You learned this in kindergarten.

Don't hog the equipment

In crowded gyms, equipment is like gold. This is especially true for limited equipment, such as squat racks and bench press racks. If you're going to squat, then squat – don't make people wait for you to take the perfect selfie or finish talking with a friend. If there's no one around, feel free to use what you want. But the minute people start piling in, be willing to share.

Wipe things down after you use them

Everyone else at the gym is begging you. Please wipe your sweat off of machines, barbells, floor mats and anything else you use. Even if you "didn't sweat that much," wipe it down. This is basic gym etiquette and reduces the smear of sweaty germs all across the equipment.

Respect personal space

Gyms get crowded, especially during the first few months of the year. But no matter how many people you're battling, you should still make an effort to respect everyone's personal space. Not only is it uncomfortable to exercise in close proximity with a stranger, but it's dangerous – one failed attempt at an overhead press could spell broken feet for both of you.

Be flexible about your routine if the gym is crowded

Can't get into the squat rack first thing? Instead of hovering two inches away from the person who's currently using it, figure out a way to modify your routine. You'll save time and avoid awkwardness, and you might end up challenging yourself in a new way (it's too easy to get stuck in the same workout routine). You can always ask the person how much longer they'll use the squat rack. If they say five minutes, great: Do some warmup moves and wait. If they say 30 minutes, don't waste your time and do something else first.

For your own good

You should definitely follow guidelines to keep the gym an enjoyable place for other gym-goers, but don't forget about making your own experience pleasant. These guidelines can keep you from wanting to shout curse words from the top of the squat rack.

Bring your own towel

Just… do this. If you do nothing else on your list, bring your own towel to the gym. It might not sound like a big deal now, but you'll realize how big of a deal it is when Sweaty McSweat finally leaves the machine you wanted but the tub of antimicrobial wipes is bone dry. In fact, you might want to bring two hand towels -- one to wipe your own sweat and one to wipe up other people's. It's gross, but it's unfortunately a fact of most commercial gyms.

Claim your space

Make it clear to others where you are working out and what equipment you are using. If you need to swing a kettlebell, run in place or stretch out on the floor, claim enough space to do that. You'll thank yourself and so will the person next to you.

If you have to leave to use the restroom or get water, place some sort of marker on the equipment you're using. A pretty universal sign that says "Hey, I'm coming back to this" is draping your towel over the equipment – the towel proving its handiness yet again.