Attending yoga class is generally less stressful than some other fitness groups, but we have some guidelines for etiquette that make the experience better for everyone.
Be Courteous of the Sacred Space

Each yoga class has a vibe. Some sessions may be quiet and reflective, and others may border on a hip-hop dance celebration. Nevertheless, here are some common tips that make class move a lot easier:

Make it a habit to arrive 10 minutes prior to class start. This gives you time to lay out your mat, gather equipment, say hello, and so on. Once class starts, not only is everyone present, but they can be present in the moment and begin the session unified and with purpose.
If you're new to class, let the instructor know right away. The two of you will discuss the general flow of the session, how and when to ask questions, if you need assistance, and other factors. The instructor will also keep an eye on you and encourage you through the class.
As odd as it sounds, some people are territorial about their class position. Try to be a bit more flexible about where in the room you'll practice. If you need to be upfront to see the instructor better, at least rotate positions from time-to-time to share that space.
Some sessions may require you to hold hands with or assist another member. If this makes you uncomfortable at first, trust that in this room, everyone will take care of each other, and give of yourself in the moment.
Conversely, respect the personal space of the people around you. If you need to spread out, choose an area of the room less populated, or stagger your mat to allow for more space between you and your neighbors.
Consider Personal Hygiene

The body is a wonderful machine, and there are natural occurrences we all have. However, be kind to your classmates and consider the following:

Clean off your perspiration from equipment. This includes mats, blocks, eye pillows, and bolsters. Always have a towel with you so you can wipe off with it or cover the mat with it, and use the mat cleaners provided by the instructor.
A little flatulence may occur, but take care not to make it a habit. Certain poses even encourage wind release as a way to stimulate the bowels. However, if you have gas trouble every time you attend class, other members will not appreciate it. Watch your diet on class day, and avoid key triggers such as dairy and cruciferous vegetables two-to-four hours prior to the session. Instead, eat a small piece of fruit with a light protein, such as almonds. You'll get an energetic boost, and these foods are easier for your body to process.
If you know that an intense workout makes your body odor increase dramatically, find an out-of-the-way corner. It's a natural body response, but planting yourself in the middle of the room may adversely affect the experience of others.
Other Top Etiquette Tips for Yoga Class

Here are a few other etiquette tips for yoga class that help everyone enjoy the moment:

Put away equipment neatly. This helps each class stay efficient.
Keep conversation during session to a minimum, unless the class is usually lively.
If you feel like humming or singing along to the music, keep your voice low unless others are singing, too.
If someone does a pose well, feel free to compliment him or her.
Keep in mind that your instructor is often flowing from session to another. If you have particular questions or concerns, schedule another time talk with him or her.