Budgeting is never an easy job to do especially at the end of the year. Most people do budgeting at the beginning of a year. But I think that it is even better if you can do it in December to plan budget for next year. By simply doing budgeting, and keep track of all your earnings and expenses just to comply with the budget you set will definitely make you richer from time to time.
In order to help you with simple budgeting or even complex budgeting, here is a list of links to some free excel spreadsheets which is helpful to plan for your personal finance.