Some people say it is more difficult to play slow than to play fast. I would say it depends how slow and how fast we're talking about. Having said that, we need to play slow movements pretty much all the time so we should spend some time practicing it.

It is easy to neglect slow music because we'd rather spend more time practicing virtuoso passages. This is a mistake in my opinion because most of the orchestral excerpts you will have to perform in auditions are either slow movements or aren't that difficult for the fingers. Sure, you'll see a few fast ones and by all means, you should practice them but the fact is that you are most likely to be asked to perform passages that will showcase your tone, intonation and musicality rather than your ability to play fast. 

When you play slow music, there's nowhere to hide so you need to make every note beautiful and in tune and think about a nice phrasing. This will greatly benefit your playing and you'll sound better, be more in tune and musical at all speeds.  

Take the slow movement of any concerto, a slow piece or an etude of your choice and make it sound great. It won't be easy in the beginning but the more you do it, the better you'll become at it. If you practice slow music regularly, playing slow excerpts will become second nature for you. 

I use to think that musicians complaining about loud volume in orchestras were over reacting. I thought they just chose the wrong job if they can't cope with a bit of loud brass or percussion. Until I got hurt myself...

Being exposed to very loud noise just once probably won't damage your ears much but having to live with it on a daily basis for years can and will cause irreversible harm to your ears if you don't do anything about it. 

So what can we do to protect ourselves? 

I've seen people walking out of stage in rehearsals and refusing to play until the brass or percussion were moved away from them!  You can try that depending on how the politics in your band work. In some places, it would work; in others it would be at you own risk...

I've personally tried negotiating with the percussionists to see if they could move a bit. They sometimes agree to move a few inches back but in general, they tend to be quite territorial about their space and rarely move even when it's the conductor asking!  So not very helpful here either...

Plexiglass screens will reduce the noise in your ears. The problem is that there isn't always space for them.  When you use a screen, make sure it's as close to your head as possible behind you. Otherwise the sound waves will "go around" it and it won't be as efficient. 

Ear plugs work but they can be uncomfortable. You can find special ear plugs designed for musicians though. They might be a good investment if you're sitting in front of the trumpets or next to the piccolo. I personally have some silicone ear plugs that I can shape the way I want. I place them in my ears without pushing them all the way in so I can reduce the noise level and still hear quite well.  For me, this is the last resort solution when diplomacy and screens have failed. I don't like it very much but at least my ears will live another day! 

Young musicians tend to neglect that issue. I know because I didn't pay much attention to it myself until I got a good wake up call once. I got hurt so bad in a rehearsal that I had to file for work injury to the orchestra management. The doctor said it was a concussion of the nerves. I took some tests to determine how my ears were affected and it was obvious that my left ear was significantly hurt. A bit like when you walk out of a dance club; you feel like everything is "muted". For me, I had headaches and extremely sensitive ears for a few weeks. Fortunately, it got better after a while. 

 I've seen many brass players losing a rather high percentage of their hearing ability after 20-30 years playing in an orchestra. Some of them are almost deaf and need hearing aids to do their jobs. Don't let this happen to you. Do your best to protect your ears even if it's a bit uncomfortable. At the end your health is more important. Ear damage is irreversible and you only have one set of ears so don't wait until you go deaf or develop tinnitus to take good care of them. 

A little typo was brought to my attention in the Mozart 4 cadenza: the last note in the first bar is a D and not a C. 
I've corrected it.

Apologies!

To follow up on the "How to increase the air intake" post,  here's a link with some interesting exercises to try.

Breathing Exercises for Brass Players - Music for Brass.com

I"ll try them myself.

Some people say that if you visualize something very clearly for a long enough time, it'll eventually materialize. I don't know if it's true but we can certainly use some visualization technique to enhance our playing and performing skills.

To make progress, you need to have a good idea of where you want to go and work to make it happen.  "Create" a performance in your head by visualizing yourself playing a great concert. Picture yourself looking strong and confident and hear yourself sounding great. By bringing these images and sounds in your head over and over again, you are in fact rehearsing them. 
Once you have a clear idea of want you want to do, pick up your instrument and try to copy that. It won't always work immediately but you'll get there eventually. 

Before you visualize your performance, do some relaxation exercises (the rhythmical breathing for example)  to bring yourself in a calm and peaceful state of mind. You will then associate the images and sounds in your head with a good and positive feeling so you are not only rehearsing the music in your head but also a state of mind that you can bring with you on stage. 

Visualization techniques are like anything else; they take time and practice to master but if you do it daily, it'll have a great impact on your playing, general mood and confidence level over time. 

For many high school and middle school students, with the end of the school year comes a band competition. I remember we took it quite seriously back then! We pretty much spend all our free time in the band room to practice or just to hang out when we didn't have class. Those are unforgettable moments and wonderful life experiences for kids.
In my last year in high school, we won first place in our category. It felt like we won the super bowl! Great memories!

Playing in a band is a great way to learn team work skills, develop tolerance and understanding  for your colleagues on top of learning to play a music instrument which takes discipline, patience and perseverance. What you learn in band will help you for the rest of your life no matter what carrier you choose.  And you make lots of friends! 

So here are a few things that the jury will look for in the competition. Work on these things together as a group and you'll increase you're chances of winning.

Ensemble and intonation: If your group is together and in tune, it'll sound good. If not, it'll sound like you're not playing the same piece. It's not only about playing the notes at the same time but to be exactly together with the same style, same length of notes, same dynamics, same articulations etc.  To achieve that, you need to pay attention to what the section leader is doing and try to copy that. You need to breathe together, listen to each other and feel each other. It's a group effort, not the addition of many individual efforts. There is a time to blend in and a time to stick out. Be wise about it.

For intonation, each section should do some sectionals and work on each note and chord thoroughly. Ask a teacher to help you if possible. It's not wrong to use an electronic tuner for some notes but remember that in the concert, you're not playing with a machine; you're playing with human beings. It's not about who's right or who's wrong. It's about how we make it sound in tune together so don't be too stubborn about the tuner if everyone else is playing at a certain pitch. 

Dynamics: One thing that I see a lot when I coach bands is that students are quite good at playing loud but not so good at playing soft. It's not that difficult to learn soft playing if you spend some time on it and it makes a great effect. Also, if you can play very soft, it'll make your loud passages sound louder because of the contrast it creates. If you can do that, you'll impress the judges and increase your chances.

Energy and musicality: It's easy to feel when everyone is into it, isn't afraid to take risks and goes for it. It immediately creates a full, energetic and moving sound. Don't just play the notes, play the music. It's the difference between a good band and a great band.  

Stage presence: The show starts when you walk on stage. You don't need to be like an army regiment but you need to look good and proper. Sit up straight, smile and look confident. Wear proper clothes and PLEASE: no withe socks with black pants!!!

Have fun!: As I said many times, if you have fun playing, people will have fun listening. At the end, the reason why we play in a band is because it brings us joy. The performance will last a few minutes for which you will spend hundreds of hours rehearsing. Make sure you enjoy yourself during those hundreds of hours too. You need to take it seriously but never forget the main reason why you're doing this.