I use Studio Plus to manage my appointments, my database of clients, my employees. It has everything you need including accounting software. It tracks everything about my business.
Client information is massive. Put as much in as you can get from them.
Session information includes who will be shooting and assisting, session subjects who will be photographed, as well as location information.
Accounting can be as detailed as you want to make it.
You can send out letters or emails to your clients in a form letter or email directly from software.
You can track orders and where each session is in your workflow production.
You can track referrels, birthdays, anniversaries.
But the best reason is it is Windows based. If you can use Word you can use this software. It takes less than 15 minutes of explaination to teach the basics to anyone. I learned it in 5 minutes and was scheduling appointments less than 10 minutes later. It is powerful.
And it imports from other software you now have and will let other software export its data to another program. Very often I export all my customer data to Excel to graph and then use for other purposes.
Go to
http://www.studioplussoftware.com/ to see more and try out a trial version.