Preparation of your composition
Many students, especially who are preparing for their first composition, always struggle with "how to start a piece" or "how to develop an idea". Before starting to write something, let's try the following steps. It might help you to answer these questions.
1. Listen to a lot of music and find the references
First of all, you need to know what genre or character of music you want to write, including the atmosphere or mood. Then you have to search different genres and find some pieces that you are interested in. Studying the melody, instrumentation, rhythm and all kinds of musical elements will help you know how to organise a piece or a motif.
2. Study the characteristics of each instrument
Choosing the right instrument is important because it may affect the tone and mood of music. You should study the technique, tone and range of pitch of each instrument in order to write a "suitable" melody for it. You should also consider the atmosphere of your music when you choose instruments. Try to make good use of the specific technique and range of pitch of that instrument to highlight their strengths.
3. Do not delete your idea always
This is a common mistake. Students always get bored with their work after listening to it several times or just because they do not know how to develop the idea. It seems this step will never end. But bear in mind, no one can write a "perfect" piece in the first attempt. We have to experiment and amend back and forth until we find a "perfect" one. Do not delete any ideas. It may be your inspiration in the future. Just leave it and keep brainstorming or ask teacher for help. We will try to help you organise the idea.
As a teacher, we cannot help students write a piece as composing is so personal and subjective. The only thing we can do is to help them organise and develop a piece and also inspire students with different types and genres of music in order to broaden their music library.