Two main things make up a good Call to Action (CTA) and the clue’s in the name: they are your call and the reader’s action.
Your call has to be firm, inviting, interesting and unambiguous. The response has to be quick and decisive. So how do you get both halves of the equation to work?
Let’s take your part first. Say you want your reader (let’s call him Fred, for simplicity, but it applies just as much to Freda) – you want Fred to book a place on your webinar. That’s your ultimate goal. Do you ask him to do that straight away? You can, if you already have a relationship or you’re well-enough known in your market that your expertise constitutes a sort of relationship (or you’ve targeted your ad so tightly that only people with at least a 35% chance of wanting to buy a ticket will see it – but this isn’t really about ads).
If Fred’s never heard of you, though, he might prefer a more softly-softly approach. So your first contact would aim to instil trust by giving Fred a link to a freebie: an ebook, or a short video with useful content. Your CTA would be a simple-but-obvious “click here for your free download”; yellow’s a good colour for obviousness.
Some gurus will tell you to have a specific landing page for that freebie, not connected to your main site, to avoid distractions and make sure Fred does download the freebie and get your follow-up “thank you” message. Other gurus, of equal prestige, don’t do that on their own sites, so presumably they don’t think it necessary – they may even hope that Fred will get distracted and see all the other shiny toys on their website.
Your CTA then takes the form of automated follow-up emails, each one with its own CTA but all leading Fred to the biggie: signing up for your webinar. I would recommend a separate landing page for this sign-up, because at this point you definitely don’t want Fred to get distracted. By now Fred knows you well, you’ve sent him lots of stuff so the law of Reciprocation* springs into action, and he’s raring to buy his place at your event.
Make it easy for him. Tell him the price before he gets to the order form, for a good start. Tell him the venue and timings before he gets to the order form, too. People want to know what they’re letting themselves in for, and if those things aren’t clear many of them will give up and not even bother to look at your order form. I bet you’ve done it yourself – or got to the order form, only to discover that the event you’re longing to sign up for happens in Timbuctoo next Tuesday at 2 am, and you can’t get to it.
You’ll never have an offer that everyone will want to buy – life’s not like that – but you’ll increase your chances substantially by being clear and allowing people who do want to buy to be decisive.
*The law of Reciprocation is one of the seven laws of influence, as discussed in Robert Cialdini’s book “Influence: Science and Practice”. If you haven’t read it yet, I urge you to do so.