How to make your website more addictive
Psychologists have proposed that our perception is formed through two approaches. One is “bottom-up processing,” which involves a direct, sensory flow of information. What you see is what you get. The other is “top-down processing,” which states that our perception is influenced by previous knowledge, expectations and existing beliefs.
Once you understand how this works, you can influence what people do without them even realizing it. This is exactly how big brands use your psychological vulnerabilities (consciously and unconsciously) against you in the race to grab your attention.
Here is how it works:

Since You Control the Menu, You Control the Choices
This is the place where we see most people making mistakes, or more accurately missing opportunity. Look at your menu. I bet it’s something like this: Home, About, Products, Services, Contact Us.
This is not bad, but what is it that you REALLY want people to do? If it’t to contact you, why not make that button more prominent and label with a call to action like Start Now!
This is what big business does.
Western Culture is built around individual choice, freedom and free will, while we ignore how we’re manipulated upstream by LIMITED menus we didn’t choose.
This is exactly what magicians do too. They give people the illusion of free choice while architecting the menu so that they win, no matter what you choose. I can’t emphasize how important this is.

Social Reciprocity (Tit-for-tat)
If you want to collect people’s email addresses so that you an market to them at a later date, there is only one effective technique. The POP-UP. And if you really want it to be effective, offer them something for free. This is called reciprocity. You offer something small to someone and they feel obligated to offer you something in return (their email address). Of course this only works if you offer them something they want. So that is why we time pop-ups to appear only after someone has been on your website for a substantial amour of time. This ensures that they re interested in what you do or offer so if you time a pop-up right and have something compelling to offer there is no better way to capture email addresses.
Incidentally, this is also, hands down the best group to market to. Since these people already like what you do, when you may them both a special, they are very likely to respond to your offer.

Bundling Your Reasons with Their Reasons
This means taking visitors reasons for coming to your website (to perform a task or learn about a certain subject) and make them inseparable from the YOUR business reasons are (selling them something or getting a donation).
Grocery stores do this, the #1 and #2 most popular reasons to visit grocery stores are pharmacy refills and buying milk. But grocery stores want to maximize how much people buy, so they put the pharmacy and the milk at the back of the store.
In other words, they make the thing customers want (milk, pharmacy) inseparable from what the business wants to do (sell them more stuff).
Tech companies design their websites the same way. For example, when you you want to look up a Facebook event happening tonight (your reason) the Facebook app doesn’t allow you to access it without first landing on the news feed (their reasons), and that’s on purpose. Facebook wants to convert every reason you have for using Facebook, into their reason which is to maximize the time you spend consuming things.

Inconvenient Choices
Businesses naturally want to make the choices they want you to make easier, and the choices they don’t want you to make harder.
For example, NYTimes.com let’s you “make a free choice” to cancel your digital subscription. But instead of just doing it when you hit “Cancel Subscription,” they force you to call a phone number that’s only open at certain times.
Instead of viewing your website in terms of choice or the availability of choices, you should view your website in terms of friction required to enact choices. Make the choices you want people to make easier and the ones you don’t want them to make harder.

Foot in the Door” strategies
This goes back to the days of door-to-door sales, when a salesman might put his foot in the door (literally) in order to prevent the homeowner from shutting it, thus ending any chance he had at making a sale.
The foot in the door principle, sometimes referred to as FITD, works like this: if you can get someone to agree to something small, they’re more likely to agree to something bigger next time.
Ask for an email address. Or a very small donation: “Would you be willing to help by giving a donation? Every penny will help”. Once the user has given you an email address or small donation, they become more likely to do something else — something bigger – next time.

Ask for a test, or help, not for a purchase
A CTA that says “Test It Now,” or “Give it a try” The way you ask for things is critical. If you can put it as a test, rather than as a purchase or commitment, the user is more likely to respond positively. A CTA that says “Try It Now,” or “Free Consultation” are very effective and your next appeal can be “Well, now that you’ve tried it, why not buy it?”
Surveys are like this too. Try the “Could I ask you a question?” technique. For some reason, people like to take surveys. If you can get someone to fill out a survey, especially one of those “what kind of person are you” surveys, you have a greater likelihood of gaining their buy-in later.

Fitts’s Law
Fitts’s law predicts that the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target.
We all know page load speeds affect conversion rates and so does the time it takes to complete an action. Fitt’s Law has two components to prescribe how long it takes to move a mouse to a desired area:
The distance to the target.
The size of the target.
If you want to increase conversions for sales or signups, either decrease the distance between elements or make buttons larger. Conversely, if you want to deter an action do the opposite.

Reduce Options
Mark R. Lepper from Stanford University and Sheena Iyengar from Columbia University offered shoppers a free sample of jelly. One day there was 24 flavors to choose from and 6 on a different day. With more flavors, 20% more people stopped to take a sample but only 3% of those people made a purchase. When only 6 different jellies were offered, 30% of people made a purchase.
If you’re unsure how many options to give a customer, start with the minimum amount that you need to complete a sale or gain a sign up then track analytics and slowly add options until sales drop off.

Social Proof
As much as we would like to think we are independent and free thinking, science proves the opposite. We are a social species like bees and termites. Science calls this a super organism. It’s a bit of a letdown, I know, but you an use this to your advantage. Social Proof is one of the most powerful tools in your arsenal.
Always include real testimonials from happy customers. Don’t make them up, people can see that from a mile away. They should also include an image of the customer (unless the pictures are poor quality) as this increases believability. Video testimonials work even better.
Media coverage, well known logos and links to articles are other powerful Social Proof that build credibility if displayed on your website. This should be displayed directly on your homepage and on sales pages.
Lastly, in your footer you should also include Social Proof such as memberships, ratings and awards.