Summarize this article:

Making a sound on a trumpet requires more than just blowing air into it. Use the proper lip technique for the best tone. Start by saying the letter M, and holding your lips together right when they touch each other. Then tighten the corners of your mouth. This is the starting mouth position for trumpet playing. Don't pucker your lips. Keep your mouth straight across. Keep your jaw loose and don't clench your teeth. This buzzing produces the trumpet sound. Use your diaphragm and push air through your lips while keeping them clenched. Produce a buzzing sound as your lips vibrate. Imagine the noise you'd make if you were imitating a mosquito buzzing. This is the sound you want. Don't change your lip position like you would when you blow air out. Keep your lips together so they vibrate and buzz. Avoid puffing out your cheeks. Lick your lips first if you're having trouble getting this sound. It won't work as well with dry lips. When you've gotten comfortable buzzing your lips, get a feel for blowing into the trumpet mouthpiece. Take the mouthpiece and press it against your lips gently. Maintain the same mouth position as before. Then buzz your lips into the mouthpiece. The mouthpiece won't produce much sound by itself, so don't worry if notes don't sound good yet. The mouthpiece detaches easily. Just twist it loose a bit while pulling gently and it will come right out. Do the same to put it back in. Don't hit it in or it may get stuck.
Press your lips together and keep the corners of your mouth tight. Push air through your lips to make a buzzing sound. Blow into the mouthpiece when it's not in the trumpet.