Write the document in plain language. If you can use two short words to say something that might otherwise take ten, then use the two words. Be clear and concise in your language and word choices. Write in short sentences.
Include a header and an introduction that states your name and declares that what follows is true. In the header, include the case name, the court number, and the court in which the case is being held. For the introduction, state your name and swear that what follows is true. For example, the start of this affidavit could be: "I [INSERT YOUR NAME] hereby swear that the following facts are true:" Do not write anything after the colon, continue to step three.
Number each separate statement after the introduction. Each statement should contain one fact about your personal income. For example, after the introduction, the affidavit could continue as follows: (1) My annual gross income per year is [INSERT FIGURE]. (2) My personal savings account contains the following amount [INSERT FIGURE]. (3) I receive other income from the following sources: [INSERT SOURCES].
Continue with a new line after each fact. Write each fact clearly and concisely in a way that the reader can easily understand.
Follow a template for help and examples. Most court clerks can provide you with a form to fill out or an example of an affidavit of income to follow. If you cannot write the document on your own, use a template. The language is generally provided for you; you simply must insert the amount of income.