1. Decide what I want to accomplish for my viewers and advertisers before beginning to design my interactive app.
2. Include a social media component in every second screen application and reward fans for sharing the app with others.
3. Build layers of increasing engagement complexity to capture both casual viewers and core fans but err on the side of simplicity.
4. Develop reskinnable templates - not one-off apps - to service multiple shows and develop apps that can run on multiple platforms & devices. [read 5 - 12] 

Last month, Delivery Agent, A+E Networks and Verizon FiOS TV launched a shopping widget on History Channel. I spoke with the iTV and t-commerce execs from each company. I'm impressed and here's five reasons why you should be too.    

Consumer Spot from Verizon FIOS (courtesy of History Channel)

1.  In-Program Call to Action: We've had shopping apps before accessed either in a widget bazaar or on a second screen but with the exception of HSN's widely deployed Shop by Remote app, this is the first big league app I've seen that gives direct access to shopping via an in-program CTA. This is critical in terms of driving usage rates as it collapses multiple consumer steps to just one: press FiOS TV.
2. Watch and Shop: Once the widget loads (quick enough not to be annoying), the History Channel live feed continues to play in a decently sized PIP so viewers can browse product while catching those parts of the show that interest them. This is much easier with your eyes on one screen versus two screen apps. [read 3 - 5]