I created a simple excel spreadsheet that calculates earnings, Expenses, estimated taxes.
Each month I enter in the total earnings it does the rest, projects an average for the year by month, compaires to the previous years month.
Then in excel you can graph it all out, a nice steady line heading up is always a good sigh in my book. I have not gone down to the level of entering each property but that can be easily done as well.
Record keeping and trends are great motivators.