One of the quick wins that will help you build yout programs more quickly, and keep them more manageable is the conditional step. It's a simple addition that allows you to build the conditional rule right into a step, rather than having a Decision Rule set up to bypass the step.
Not only is this quicker and easier to set up, but it leaves your programs looking neater and cleaner, and it is much easier to add later if you decide to make changes to a program to add a condition to an existing step.
Build your program as you normally would, but in the Action details for your step, you will now (or as of the coming release) see an Action Condition option. That is where you add the rule for whether the step is to be run or not.
Clicking "Add" brings up a configuration box for the condition. You have a full set of options here similar to your set of options in building a Decision Rule. You can look at data that is known about your contact in order to guide personalization, whether they responded to a prior marketing campaign, whether they have submitted a form or registered for an event, or whether they are a member of a specific group.
Once you decide how you want to define this condition, you have a set of configuration options, again similar to the options on Decision Rules. In our case, we're going to send Email 2 if Email 1 was not clicked on, so we select that option and choose the specific email we're looking at.
With that in place, you are all set. You can have the action execute only if the condition is met, or only if the condition is not met. Using this should allow you to simplify how you build your programs, and keep them even more manageble and clean.
I look forward to your comments on this feature once you've had a chance to try it after the February 22nd release.