Tone

Tone can be changed many ways. A mouthpiece for example is an important and crucial object to pick. The mouthpiece you buy depends on the music you play and whats comfortable to you. There are many sizes and you may customize your own to what feels right and to what you need from a sound. You could be playing on a mouth peice that you hate but play pretty decent when you can being playing comfortably and very well with another mouthpeice.

Buying a trumpet alone is so important. As a beginner a standard yamaha would do great. As you experience you want to know exactly what you are looking for. You have to know the sound of the music that you play. You have to know what professionals use so that you can get an idea of what you need. 

The weight of the trumpet and the type of material you look for is crucial. The weight of the bell on each trumpet. A trumpet that has a good vibrating bell will make the tone bright.