Can anyone share your opinion on key features that are encourages visitors to take actions.
Just like your web site, your question has me ask what actions would you like them to take?
Some sites like Facebook want you to join.
Amazon has stuff for you to buy.
WebMd has information about your condition.
Wikipedia has information about well, everything.
Each one takes a different approach to offer the visitor choices on their next action but without you telling more my answer is to look at sites that offer what you offer for ideas. Who do you envy?
I agree with rproffitt, you need to first think what it is that your business/website offer to people and base all your research on those criteria.
Search for the top 10 sites related to your industry and see what they are doing. Decide if this will fit into your profile and then start planning your site. Another idea is to then search for certain criteria and see who lands in the top 5 of your searches. Then look at what they do and follow suit.