A user interface must be as simple as possible. This can be very difficult and can require tremendous effort. In some cases you might need to work with the business, legal or technologist to accomplish this. Remember that from the user's perspective, simplicity is always more valuable than innovation.
What are you trying to communicate? Can it be misunderstood or misinterpreted? User testing can help to fine tune your experience to be clear and concise. Users will abandon or view an experience as negative if it is not clear what they are meant to do and/or understand.
The interface should contain as few steps as possible to accomplish a goal. Every single screen should be focusing on one particular task. Keep non-essential actions in the background or on another page, because you need the experience to help users focus on what they should be doing. Ask yourself; do I need the user to complete all these tasks? Be ruthless in your pursuit to minimize the user's effort.
The UI design needs to be consistent and almost familiar. Using common patterns can help, for example sign in is often in the top right, logos are often in the top left. These help users to find information based on their previous experience. Imagine how frustrating it would be for a user to see a SAVE button in red, or a CANCEL button in green. A design system can also be used to help maintain consistency and can reduce effort for the user and the designer. All the visual elements like the colour scheme, dialogs, fonts and navigation should follow a consistent pattern to allow a smoother user experience.
An ideal UI design does not create friction for the users. It should provide a pleasant experience keeping its ‘design features’ in the background and bringing forth great usability. The design should not be a cause of any interruption or delay in the process of doing the task at hand.
UI design should provide feedback to the users to indicate whether their interaction was successfully done or not. It can be used to provide important information, nudges or next best step. This feedback can be in various forms, such as a notification, alters or empty states. It can even be a change in state, colour or even a small micro animation. The goal is to communicate, so users feel confident that their action has had the expected result. Users should always be aware of where they are, what has happened and what they should do next.
Minimize Cognitive Load
The UI interface should relieve the users from thinking as much as possible. This goal can be achieved in many ways such as:
As the famous Miller’s Law states, an average person can keep 7 items in their working memory. So the information should be divided into smaller chunks. A 10-digit number for example, should be broken up into 3-3-4 to make it easier to remember.
The design should enable a user to complete their task in no more than three clicks if at all possible.
Universally recognized items should be used wherever possible to maximize usability and user recall. For example a bell icon, commonly known as a symbol, should be used to indicate similar function. Using common symbols to represent something else will only result in confusion for the users.
Design with accessibility in mind; ignoring it will only cause issues down the road or in some cases lawsuits or penalties. We are accountable as designers to our business and users to be inclusive in our designs. A small font size or a subtle color might look nice, but remember that at least 25% have either a permanent or temporary disability. And 25% is a large market to miss out on.
For a design to be successful, it must be first validated with the help of users. You should know whether users are able to navigate and complete common tasks without assistance or instructions. User testing is one of the most important activities a designer should do, and is often overlooked. It can be done with relatively low effort and/or cost, given the impact and cost savings it can have on the business. According to NN Group, 3-5 users can find up to 80% of the most common problems in a design.
The user may be using any brand of device, operating system and browser. So the design must be able to work and/or be optimized for all commonly used devices, operating systems and browsers. It is also important to consider speed and performance, as some users might not have access to high-speed internet.
Anticipate the Mistakes
You cannot imagine having all the users successfully follow your design. There will certainly be people who will make mistakes. So you are not supposed to let them fail to do the intended task just because they couldn’t understand how to do that. Your design should have the ability to predict such situations and be prepared to provide alternative means to complete a task. This can be as simple as providing chat support or a call in option.
Know the Users
For any specific product, a UI design must be planned according to the target users. A product is often designed for a specific group of people, who vary according to their demographics, interaction skill level, education, etc. You cannot expect the same level of vocabulary in voice responses from kids and adults. Similarly, an app designed for doctors will use different modes of interaction as compared to the one intended for the farmers.
A good UI design should be able to interact with different types of users in a way that they like. A product will often meet people from different cultures and demographics. It should have flexibility to change, based on a user’s behaviour or intent. For example, when a user clicks an ad, the header of the corresponding site should have consistent messaging, or an app can provide different colour schemes from light to dark mode.
In conclusion, a successful design is not just taking some elements and putting them together. It actually requires your careful consideration to make it stand out from other similar products in the rapidly evolving market. The above-mentioned principles will help define your design. Even after achieving initial success with its launch, a design will constantly need to keep updating in the light of these principles, and keep evolving based on feedback and analytics.