Nudge is a method used to gently push a user to modify their behavior or to guide in a certain direction.
You might not even realize but you have been the subject of a nudge without even knowing. These days nudging is becoming an effective way to get people to modify their behavior.
Here are some nudging techniques used today:
Pre-selecting beneficial defaults helps the user make less decisions thus reducing their cognitive load and reduces chances of indecision by thinking too slow. An example for this is when you are creating a form you could pre-select the option that will do the least harm. This way the user will not have to ponder their choices too much but is being guided by you.
Provide immediate visual feedback of the consequences of the user's actions. A example of this technique can be seen when you try to unsubscribe to newsletters. Done correctly they will show you what you will be missing if you do continue to unsubscribe. This technique has definitely worked on me a few times but I will be stronger next time, I promise.
You can align your goals with incentives to entice and nudge the user to a preferred action. You have probably seen this when being asked to take a short survey and receiving a monetary incentive. Care must be taken to make sure the incentive promised is enticing enough for the user to dedicate their time.
Providing clear and meaningful choices to make the user feel like they are in control. Having the right information architecture in place helps nudge users along to their goals. Giving users multiple ways to get to their goals is also a great way to provide structured choices.
Making the goals clearly visible helps improve goal completions. Progress bars are a great visual element to provide visual feedback to the user. As the user progresses they are positively nudged to complete a task.
Of course there are designers who use these techniques for nefarious reasons as well. The users need to be respected and not taken advantage of by using dark patterns that hide bad intentions.
Used correctly nudging is a great way to guide users to make the right decisions.