How do I wake up a closed Macbook reliably?

I have a Macbook Pro (Retina), and a Samsung DisplayPort display, both new. They work great together, when I can get them to work.

For example, if I plug in the monitor, and then open the Macbook's lid, it wakes up and sees the second display and everything's great.

But usually I want to keep the Macbook lid closed, and use only the external display. This, too, works great, when I can get it to work. Unfortunately, I haven't figured out a reliable way to do it. I plug everything in, and then hit keys on the keyboard, and press the display's settings button, and cycle its inputs, and click my mouse button, and everything else I can think of, and eventually after a minute or two it sorts everything out and it works great.

Surely there must be some simple and repeatable procedure for waking up a Mac with an external DisplayPort monitor. What is it? Is there some order of plugging in the power cable, plugging in the DisplayPort cable, hitting the monitor's buttons, pressing a key, clicking the mouse, etc., that I should use?

Back in the PowerBook G4 days, I could just plug in an external DVI display, hit any key on my external keyboard, and it woke up immediately and everything just worked. Today, apparently, things are more complex, because that procedure no longer works.