Q:

What is the proper procedure for showering in a gym locker room?

This is going to sound like a stupid question. I apologize. But I've had it on my mind for a while and it needed to be asked.
My question is: how do you use the shower at the locker room at the gym?
I told you it was stupid.
But really, I've had gym memberships for a total of about 5 years during my life (not consecutive). I've gone frequently and worked out, but I've never used the showers there. Why not? Honestly, I've just been too nervous about it. It's not so much public nudity itself that makes me nervous. It does make me feel weird and a little self conscious to take my clothes off in a room with other people in it, but I don't think other people really care that much. What does worry me though is the possibility of committing some kind of social faux pas or perhaps even exposing myself to some kind of safety hazard.
Some of the things that have run through my mind as I contemplate taking a shower at the gym: 

Where do I keep my clothes? 
If in a locker, should I wear a towel between the shower and the locker?
Where do I keep the towel while I'm in the shower? Not every place I've been to has somewhere to hang it.
If there are no private showers, is it normal to shower in a bathing suit or similar attire? My current gym has private shower stalls with curtains, but I've been to gyms where the showers were more community style.
Where do I keep my cell phone/wallet/keys? I can't really bring them with me into the shower, so I suppose I'd have to keep them in the locker. But is that safe? If someone broke into my locker while I was in the shower, I'd lose everything valuable and I'd have no clothes.
If I use a shower that strangers have used, are there any possible health repercussions? Do I need to wear sandals to protect against athlete's foot, for example?
Is it normal/OK to perform other grooming functions, such as shaving, or brushing your teeth, in a gym locker room?
Etc

So again, in summary, what is the safest and most socially acceptable way to use a locker room at the gym?
It does surprise me how anxious I feel about this, considering I'm usually pretty laid back about most things. I have been to the hot springs and even bath houses in Japan, when I was there visiting friends. But I felt less anxious about that because I was accompanying people who knew what they were doing, and I just did my best to imitate them. When I go to the gym locker room by myself I feel completely out-of-sorts. I feel like everybody else in the world has read some secret manual about how to deal with this and nobody ever handed me a copy. Please help!
If there's some cultural ambiguity about social customs, please assume for the purposes of this question that we're talking about the United States.

A:

Short answer is this: when in doubt, ask management.  A longer answer includes some general principles:

Use your locker to store clothes, and anything you don't want in the shower with you.  Lock your locker and take the key with you (if it's not a combination lock).
Wear a towel around your waist going from the locker to the shower.  While no-one is likely checking you out, you don't want to advertise either.
Hang your towel on the shower stall door or on top of the shower head if there isn't a towel hook.

As far as community style showers go, it really depends on your comfort level.  More than likely in a gym most people in the shower area with you don't really want to see you.  As long as you aren't looking all around and focusing on getting clean, you won't cause any breach of etiquette.
As far as clothing in the shower goes, what is the purpose of the shower area in your gym?  If it is simply to rinse before and after going to the pool, use a bathing suit.  If it is to clean off the sweat from intense training, being in the buff is OK.
As far as health risks are concerned, evaluate the cleanliness of the shower area.  Gyms that routinely disinfect the shower areas will be about as safe as your home shower would be.  However, if you see evidence of less than stellar upkeep, keep some flip flops on.  Use soap and warm water.  Anything more falls under safety concerns.
Last, but not least, if showering at home suits you best, do it.

A:

I've been in and around the military for 25 years and I've used gym showers for more than 30. Despite this, I still have my own questions about the unwritten etiquette of showering in gym locker rooms.
The etiquette differs greatly based on sexual orientation, but the universal rules are these:
Golden Rule: Boners make public showers awkward.
Other Rules:
1) Always shower before and after using the swimming pool or sauna (wet or dry).
2) Always wear a towel when going to and from the showers (and/or the sauna). Some guys may want to see you in the buff, but none are going to tell you. The rest of the guys simply don't want to see you naked.
3) Wear flip flops or some other form of foot protection to protect you and others from the spread of foot fungus and other unmentionables (see rules 8 and 9).
4) Talking is fine, in or out of the showers. Just don't talk about sex, women, other men, or anything that is likely to cause arousal. See Golden Rule.
5) Even if someone is putting on a show for you, don't stare (especially if it arouses you -- see Golden Rule).
6) Keep your hands to yourself. Touch only what is yours. Sharing a bottle of shampoo or body wash is okay, but don't make physical contact with the other person.
7) Don't tug on your junk, not even a little. Even if it's cold and drafty in the showers and you are self-conscious about shrinkage. Even though we're not looking, per se, all guys can all tell when someone has been tugging on it to compensate for cold-air shrinkage. Don't spend any more time or attention on your junk than is required to wash and rinse it.
8) Don't masturbate in the shower. Most people don't want to see you. Even those who do want to see you don't want to step in your man goo.
9) Don't pee in the showers. No one wants to smell the acrid smell of your urine. And we don't want to watch it swirl down the drain with your shampoo suds. And we don't want to step in it, either.
10) Take all your stuff with you. If you shave in the shower or use the last of your body wash/shampoo, take your trash with you. If you're one of those peculiar types who wears his undies, jock strap, or gym shorts to the showers, make sure you take your crotch sweat-soaked clothing with you.
11) Dry off as much as possible in the shower and keep your butt facing the wall while you do it. Because very few guys want to sit on the bench and see your naked butt or junk at eye level while you dry yourself off.
12) Don't pay compliments to others on their bodies or body parts. If a guy has great definition in his pecs, delts, quads, or (especially) glutes, keep it to yourself or mention it outside the locker room. Even as much as I enjoy having someone flirt with me, I don't want it to come from the guy next to me...in the locker room at the gym. It's creepy.
If a guy is straight, remember the Golden Rule. If a guy is not straight (gay, bi, curious, etc.), there are caveats to the rules, but only if it is known that the other guy is not straight.
These are the rules I have come up with based on 30 years worth of observations and experience. 

A:

Locker rooms are a comfortable space for most men, and a terrifying space for some.
If you are in the latter category, don't use the locker room or use it but don't shower.
The good news is as long as you don't stare it is hard to violate any sacred rules, because there are none.
Having showered in dozens of different locker rooms, layouts vary.  Regardless of shower type (stalls or open), the basic procedure is the same.
You put your street gear in the locker and go work out.  When you are dine you return to the locker and get naked, stowing your sweaty gym gear in your gym bag/back pack.  I have showered in gyms 4 to 7 days a week for more than ten years and owing to work travel I go to lots of gyms.  I have seen lots of guys skip the shower but I have never seen one  put on a swim suit to shower in.
Once you are stripped, most guys put the towel around their waist as they walk to the shower area.  Others kinda just hold it in front of them.  Some hold the towel at their side or put it over the shoulder.  There is no rule.
Once you get to the shower area, there are usually hooks in an area near the stalls, right outside the communal shower room or sometimes in the shower room on the wall opposite the shower heads.  A few places have hooks inside the oversized shower stalls.  You just look around and put your towel where others put it.
In the shower there are no special rules except no staring.  No staring doesn't mean you can't look at people.  You should look your shower mates in the eye, however.  If it is an open shower you shoul pick am open shower head as far distant from the other users as possible.  This gives others space, but it is not an inviolable rule,  One guy at my gym for some reason apparently needs to use the same shower head, and if the shower is empty except for me, upon entering he will take the head right next to mine if it is the one he likes.  I figured this out at some point and if I see him in the gym and expect our showers will overlap, I go to a head on the otherside of the room.
You can and should bring your own shampoo or body wash.  Very few bring in bar soap.
The trip back to the locker is the same as the trip into the showers.  If you want, you can shave, etc.  Some guys do this in a towel.  Some do it in underwear only.  Some do it in pants but no shirt.  Some do it fully clothed.  A few guys like to do it naked.  It is a choice.

