A well structured budget conveys a project that is organized, planned out, and do-able. Here's a sample:
Add line numbers to left-most column for reference.
Use an outline format to put categories and subcategories in adjacent columns.
Include a Notes column to explain how you calculated each figure.
Include subtotals for each category.
Include in-kind and donated services, including your own time.
Estimate all expenses, even if roughly.
Sum the columns and rows.