Imagine that you have just composed or learned to improvise an organ sonata. The next step would be to add an introduction.
When adding introduction to your composition or improvisation, choose a slow tempo and a contrasting theme and texture, perhaps in chords. The introduction does not have to be long - 1 page (1 minute) is enough. End on the Dominant chord in the main key which prepares for the entrance of the Exposition.
By the way, the material from the Introduction can also appear right after Exposition and at the end of Coda. In such case, end the Coda with a bang - perhaps a brief reminiscence of the main theme. This approach will make your sonata truly dramatic.
If you want to compose or improvise a Coda in your sonata, you can briefly recall the main themes of your piece (perhaps in a distant key, such as flat II). Then use a sudden Enharmonic modulation to return to the tonic key. In a way, your Coda could be like a second Development section (Beethoven's invention). End your sonata perhaps with the repetition of the closing theme.
For the best results, try to look at actual compositions of Beethoven, Mozart and others. If you analyze the works of your favorite composers, you will find many ideas when composing a sonata with or without introduction or a Coda.
By the way, one of the most famous examples of sonatas with introduction and a Coda is Sonata No. 8 for piano by Beethoven. Here the composer uses a slow introduction before and after the exposition and even after the Coda.
Beethoven's Codas tend to be much longer than by other composers. In Codas he can try to exhaust the thematic material even further than in the Development section. If you do this in your own organ sonata, it will truly be quite dramatic.
Try these tips when composing or improvising an introduction or a Coda for your sonata today. At first the process might be a slow one. However, the more you compose or improvise, the better and faster you can become. You just have to remember your goal, take action, persevere and you will succeed.
By the way, do you want to learn to improvise in the style of Bach? If so, I suggest you check out my 9 day mini course in Keyboard Prelude Improvisation.
Or if you want to learn my special powerful techniques which help me to master any piece of organ music up to 10 times faster? If so, download my video Organ Practice Guide.