The key to a truly great call to action is that it DOESN'T actually CALL FOR AN ACTION AT ALL.
In fact, people started to use this term "call to action," because it makes it sound like you're ordering someone to do something for you and that's not what persuading someone to buy from you is about.
If you want to persuade someone to buy from you, then you want to really remind them what the VALUE is of what they're getting.
So a truly irresistible call to action isn't about reminding someone the action they need to take. It's reminding them what they're gonna get when they do that action.
"Get My 101 User Experience Lessons Free"
…is a great call to action to remind people what they're getting. That is a no-brainer.
That is much more persuasive and more compelling than, in contrast, saying "Submit form."
Tactics to strengthening CTAs:
1) Incorporate 'Click triggers' to reduce anxiety. For example, when people are looking at that button and they might worry about something that is on their mind; something that can hold them back. In this case, you can incorporate such things as 'No Credit Card Required', 'Money Back Guarantee' or 'Cancel Anytime.'
Those 'click triggers' help people feel okay about moving forward.
Another thing that you can add in to your call to action to make it that much more appealing are icons. Icons is a great way to draw the eye in.
And then a third thing to consider when you are creating an irresistible call to action is about visual contrast.
People tend to obsess about colors, like whether they should be orange or they should be blue or whatever.
Colors is not really what matters at all, but what does matter is that you minimize the clutter around the call to action so it's the number one thing that they see. You just need to make sure that it's a high contrast, so it stands out from the rest of the page.
A button or a call to action that just blends into the background or worse, matches the color scheme of the rest of the page won't be recognizable as an actual focal point and hone in on it and that's what you want them to do.
So if you bring all of those elements together, you can increase the visual, cognitive, and emotional appeal of your call to action.