Mobile App Design - The Thumb Rules

In just a few short years, the world of mobile computing has brightened with the many colours of different apps. Mobile-phones come equipped with apps for every imaginable purpose. A user is practically flooded with apps catering to his every possible need.

The app is either pre-installed on the phone such as address book, calendar, calculator, or can be downloaded from app distribution websites such as app stores. What makes some apps more popular than others? How is it that certain apps engage consumers while others never get noticed?

While functionality is a crucial aspect, the other deciding factor is undoubtedly the user-interface and experience that the app extends. The journey of an app begins with the user-interface and the experience it creates. It is the first and sometimes the deciding encounter between the user and the application. 

Mobile interface design is much more than great pictures and perfect typography. The essence of mobile interaction design is the way an application responds when the user is most dependent upon it. For a great user-experience it is essential to understand the primary technical difference between mobile device operating systems and operating systems used on laptops or desktops.

The mobile operating systems usually are limited in their multitasking capabilities. Usually on mobile devices only one app is active at a time. When another app is started, or the app is interrupted by another app  (for example, a phone call), the app that was running gets put in the background. It remains in the background until the user specifically accesses it again. If it remains in the background too long, or if available memory gets too low, the operating system may kill it. A user may toggle between apps on several occasions. While designing the app  the developer  needs to handle this aspect carefully and ensure that  users don't lose data or get unnecessarily interrupted while toggling between two apps.

Another important experience factor is how long does it take for the app to load. A swift app always wins the heart of users than a sluggish slow app.

It is also important to keep in mind that the computing resources (CPU, memory and storage-space)of a mobile are of a lesser scale as compared to a desktop. Due to relatively lower computational powers in mobile the app has to be designed ensuring that it uses these resources minimally.

Mobile devices have a much lesser screen space than computer screens, this makes creative designing a little challenging. While horizontal and vertical scrolling tries to overcome the size aspect, it is important to remember that horizontal scrolling is not a very natural action amongst users. Users may not easily use horizontal scrolling to explore options not available to them on screen. Hence scrolling options have to be used very judiciously. It is essential to therefore plan the user's interaction with the app very meticulously. Screens should focus on one, or a very limited and coherent, set of tasks that the user can or would want to do. Navigation should be planned and designed so that it is obvious to the user how to proceed to the next task. If a task requires multiple steps, those steps should be designed as distinct screens, and the user should be guided through the screens needed to complete the whole task.

Every mobile device uses a different set of hardware and software setup. The app can sit on any device. Example – Android and iOS phones. The design should therefore be ubiquitous and fully capture a device's capabilities and adapt to its unique characteristics. Users expect their application to run smoothly even when they change their devices. An app should adapt to the entire ecosystem of a user's chosen operating system. 

Mobile is an extension of an individual, it is his constant companion. It is essential to remember this aspect while designing mobile apps. The app needs to smoothly blend into a person's life without disrupting or disturbing his life. Every aspect of design should evolve around this aspect.

A user can be in different situations while using the app. The app has to be sensitive to this fact and have options to adjust itself according to the setting it may be used in.

The world has shrunk and people are globetrotting like never before. It is important for the apps to adjust to this trend and localize as per the need. Example - displaying the currency as per the location, time settings as per different time-zones, language settings are just some of the points that can add to an enriching user-experience.

Apart from the above points a mobile app should conform to best UI practices and UI guideline. It is important to pay attention to basic design principles such as consistency of icons and text, appealing color codes, simple easy to use features and navigation.