Making music is no easy task by any means, but making orchestral music is a whole lot harder than just putting together beats and etc. Before you even think you are ready to put together music like this, you have to have a great working knowledge of music theory and harmony. When writing a complex piece like this on the computer, you are going to need a lot of different software. Make sure you have all of the necessary tools. Some good software examples are Finale 2010, Sibelius 6, and MuseScore.
Once you have gotten the software you need to create your music, you will need to select the instrumentation you want to use. The biggest part of the symphony are; the orchestra, light percussion, and winds. You have to create many different themes and interlink them. However, you need to watch for errors, skips, and cadences that don’t make sense. This is why it is absolutely imperative that you have a really good ear for music and a wealth of knowledge to back it up. It is very easy for a beginner or somebody who doesn’t know a lot about music to miss errors on a track. You really need to learn as much as you can before attempting to put together music like this.
The creativity process is by far the hardest and the longest process to get through. You will end up with a lot of different themes and variations, but eventually they will become one long movement. Here are some great techniques to try; start adding dynamics, rhythm alterations and solos reflecting different themes and melodies. During this process, you should be listening to other symphonic works because that tends to aid in coming up with ideas.
The last step you need to do is; go through each movement and make sure you have no bad passages or progressions that are off. After you feel that your work is complete should take it to a high school or any group that has an orchestra and get them to play it for you. Usually you will have to go back and fix some things a couple times. That’s an absolutely normal practice; nobody gets it absolutely perfect on their first try. Something always has to be tweaked. After all your tweaking and editing are all done you are ready to take it to a music publisher. After the publishing process is over, you are finished. You have created your own symphony from scratch.