The First Book of Practical Studies by Robert Getchell is a book full of simple and wonderful melodies. Each piece is musical and not very long. While it might appear to be a beginner's music book, it has also been used by advanced players to work on the areas of endurance, sight-singing, sight-reading and transposition. The melodies become gradually more challenging, but they move at a easy pace.
Here are some tips foR using this book for Endurance, Sight-singing, Sight-reading and transposition.
Endurance
The best way to build endurance is to play and rest. It is a balancing act of not only playing, but resting as much as you play. You want to work on building yourself up, and not tearing yourself down. You do this by learning to play Getchell's melodies without a problem technically. Then you play one, rest for that amount of time, and play the next one. You do this within a set amount of time such as 30 minutes. Then come back in several hours and continue. Doing this every day over time will increase your endurance.
SIGHT-SINGING
Sight-singing is the ability to read the music and sing the pitches and rhythms correctly. You don't need to be a great singer to do this, but it is an important skill to develop, because on the trumpet you are the one who makes the sound. Unlike other instruments such as the piano, those notes are already there. On the trumpet you need to be able to get the sound image in your mind of what you are going to play. It is also the best time to correct your mistakes before finding them on the trumpet.
SIGHT-READING
Sight-reading can be a very important skill if you wish to have the ability to perform music placed in front of you without any prior practice or advance familiarity with the music. This is a learned skill, and the way to become a better sight-reader is to read through music you aren't familiar with on a daily basis. You also need to do this in a wide varity of styles with different patterns of rhythm and pitches. This book helps you do this. You can randomly open a page in the book, and after briefing looking it over try to play it, or do sight-singing on it first.
TRANSPOSITION
The skill of transposing a piece of music on-demand can be a very useful. Say you brought your trumpet to a friend's house who plays piano. You would like to rehearse with your friend, but there is no trumpet part. You could read off the piano part, but that's in concert pitch, also known as Concert C. If you play what is written you will be not playing the correct note, because they need to be transposed up a whole tone. For example, if the piano part has a "G" written, you must play an "A" on your Bb trumpet for the pitches to match. Using this book to take melodies you are familar with, and learning to tranpose them to at least Concert C will be the most useful to you. There are trumpets in different keys, and you can be expected to transpose in several different keys, and this book can be used to practice them as well.