Most of the time you will place the call to action above the fold. However, this doesn’t work for all situations. Sometimes you need more space for convincing and explaining. The idea is that the user has all the confidence he needs to make the intended action. Sometimes a little persuasion around the CTA helps before they take the next step and click, EG giving some more insights, showing trust indicators such as testimonials, … 

So, choosing the correct placement starts with knowing your target audience and how much information they need to move forward.

On some pages, you will have more than one CTA. Write out all the CTAs on the page and rank them in order of importance. What is the main goal of the page, and which button offers the highest chance of achieving that goal? Are there any CTAs you should delete? If they aren’t getting click-throughs and aren’t your primary focus, they should go.

Simplify your page and keep the number of CTAs low.

When faced with two doors, and one said it entered the auditorium, and the other had no markings, you’d be reluctant to step through the unmarked entry. Let your site visitors know what happens when they click on your CTA buttons. People don’t usually like surprises when it comes to CTAs.

Take away any doubt about going to a form, another page or a shopping cart.

Negative space on your page helps draw attention to the CTA button. Set it off by itself, so the user’s eye lands on it. Remember point 2 and rank your CTAs.

Don’t place two similar CTAs next to each other. Competing for attention. It will confuse the visitor and result in lower conversion rates.

An essential part of this tip is including specific action phrases in your CTA. It may be tempting to use something cute and crafty, but action verbs are what propel the reader to actually take the action that will result in more conversions.

1. Avoid using the third-person tense.

Using the first or second person tense makes your CTA much more conversational like you're talking to a friend. Addressing your visitors like they're already a customer and a part of your company's family is a great way to encourage them to take the actions you want them to take. So, talk to them (second person) or put yourself in their shoes (first person).

2. Create a sense of urgency.

Without a sense of urgency, your audience will have all the right thoughts and intentions of signing up, downloading, contacting you, but won't in the end.

However, creating a sense of urgency doesn't necessarily mean inspiring panic. Offering time-sensitive deals and discounts, a referral incentive, or a sign-up bonus can be a friendly way to create a little urgency on the part of your customers.