I recommend writing down the whole process of organizing the tour. First, categorize the expenses into three categories, namely (a) pre-tour expenses, (b) actual tour expenses, and (c) post-tour expenses. Expense (b) represents your direct expenses, while (a) and (c) are considered your indirect expenses. Do not include advertising expenses in the pre-tour expenses; keep it under a separate head.
Further, break down the expenses where possible. The major portion of your expenditure will be in category (b). You can divide this into subcategories such as fuel, lodging and boarding, food, medical, transportation, staff salaries, etc.
Regards,
DVD