Here are some core applications that a Realtor or a Solo Entrepreneur needs in their arsenal to look professional:
1. Customer/Client Relationship Management System (CRMs)
I find it mandatory that an entrepreneur has a CRM. Batchbook has fit my bill since my first CRM system as an Access database. What I like about this Batchbook is that you don't need to have an IT background to make changes to the system. It can connect to Facebook, Twitter, and LinkedIn to anyone entered into the system. Also, there is a true relationship managment behind this system. You can connect important relationships with your contacts and even your deals! There are many advantages to this "unknown" system.
2. eMail Newslettter
Batchbook and MailChimp really go hand in hand. They sync very well so I have one centralized database with Batchbook; but, can do my newsletters through MailChimp using my centralized CRM system. I like MailChimp because of one simple word : FREE. Yes, I said free for 12,000 emails a month. Now if I ever get over 12,000 emails a month, I will happily pay the fees that MailChimp details on their site. Also, this eMail system allows for integration of YouTube videos. I find this invaluable.
3. Mileage Tracking
I primarily use Expensify for tracking my mileage; but, you can also track all of your expenses for your business through this application. I use my business credit card to track the rest of my expenses. I like Expensify to track mileage because it has a map integration to the system that calculates the mileage for you. All you need to know is where you started, where you went, and where you ended up.
These are the tools I use to simplify my life. I am not endorsing any particular one; but, I am saying these are the best that I have found for my entrepreneur kingdom.