The Big Four
When I say the "Big Four," I'm talking about the four applications that by default are available when you press one of the hardware buttons at the bottom of your PalmPilot. To me, the ability to press one of these buttons with the unit off and have it turn on and go to that application is one of the most user-friendly features of the PalmPilot. And, I find that I use the Big Four more than any other applications, so even though there are ways to re-map these buttons to run other applications, I've still got them pointing to the same four they did right out of the box.

Categories
The key to using the built in applications is the use of categories. Categories give you a way to separate the information stored in the built-in applications (except for the Date Book, which doesn't use categories) into logical categories. The default categories when you first start using the PalmPilot are Business and Personal. What categories you use really depends on the type of information that you're storing in each application. What you need to remember is that categories give you a way to quickly access information once its been placed within a logical category. I have a "Book Notes" category in my Memo Pad where I kept all the notes for when I was writing my book. While I could have kept these in the "Personal" category, this allowed me to quickly locate and add/edit information to the Memo Pad records that I needed to get to.

Address List
The Address List application is probably my most used of the built-in applications. Before I got a PalmPilot, I used to carry a little card in my wallet with my most called phone numbers, and was constantly scratching out old entries and penciling in new ones. What a mess. With the PalmPilot, I can now store not just my most used phone numbers, but all of my phone numbers. I now add any phone number I ever use to my PalmPilot, if I ever think that I'll be calling that number again in the future.

One of the more interesting features of the Address List application is the ability to rename the four custom fields to whatever you want them to be. Available from the Options menu, this allows you to rename the four fields that appear at the bottom of each Address List record. While some folks have said they'd like to see more than four of these, you can almost get the same result by putting extra bits of info in an attached note, since the note appears at the bottom of the record when you first tab on it. And, since the Find feature will search notes as well as the rest of the record, the only thing you lose by not having extra custom fields is the ability to call/use those fields from other applications.