An interface is your products’ window to the user. It is a tool which in the ideal case fulfills the users’ expectation and allows him/her to use your product or system in a satisfying way. Ease of use and giving the user control are important guidelines for designers but unfortunately they are also very vague. Furthermore, what might work for one interface, might not for another.
These reasons make it hard to define specific guidelines. Everything depends on the product or system you are designing. However, there is a set of principles which prevent your interface from becoming a nightmare:
1. Design an obvious starting point
A user must know where to start his interaction with the content or system. Obvious can be defined as an attribute that stands out through size, color, font, orientation, shape or movement. Every encounter with a new interface needs a starting point because it involves a learning process for the user and the user does so in finding patterns in the details.
2. Design on obvious exit or stop
Always allow the user to reverse an action or to end the session. The reversal shouldn’t be visually prevalent, but it should be omnipresent, subtle and clear. To give the user the power to exit at any time might give him/her the needed confidence. This principle is also called forgiveness. It means that generally any action can be reversed. People need to feel that they can try out systems and interfaces and if an error has been made or a wrong route has been taken, they can reverse their action easily.
3. Design for consistency
Within a system or interface the user must be able to quickly identify a logic, rational patterns of relationships between user action and effect. This principle is based on human logic and cognition. When pattern are consistently and rationally connected to action and content, user will recognize these patterns and their meanings. Consistency also diminishes learning times and effort and gives the user confidence in the system. The most important consistency to strive for is the consistency with the user’s mental model and expectations.
4. Use the power of familiar interface conventions
We are used to interfaces and we don’t come to an interface as a blank slate. We have incorporated interface language, words, phrases, images and conventions. Think of menus on websites: we are used to find them somewhere on the top. A website with a menu only in the footer would cause disorientation and difficulties. As a designer we should be aware of these conventions and try not to violate them. Existing conventions can be built upon and extended. If we decide to ignore convention we should only do so when we it gives us a particular advantage.
Here are 40+ websites with unusual navigation!
5. Never forget feedbacks
There is nothing worse than an interface that doesn’t give you any feedback after you have taken an action or completed a task. Confirmations like “your changes have been saved” or “your registration has been successful” are reaffirming, comforting and tell us that everything is proceeding according to plan. Feedback should be noticeable. The prominence should be proportional to the importance of the action. It should also be immediate.
6. Prevent the user from getting lost with landmarks
Landmarks build upon user’s ability to create a mental model of their experience. We are spatial thinking beings and to move around we use reference points. In interfaces this is no different. Give your user clear landmarks which are available at all time (home-button). Landmarks support the users’ cognitive map, and help them identify where they are and where they can go. They are important for spatial navigation as well as in procedural knowledge because it relates to the logical or non-spatial mapping of information.
Example: take the process you go through when buying a flight ticket. If the interface gives you good clues of where you are at the moment and what the next steps are you feel save and confident in your tasks.
7. Design with proximity in mind
Cluster similar items spatially as well as conceptually. A user should be able to perform similar actions without having to cross great physical, spatial or conceptual distances. The principle of proximity can be divided in:
- Spatial proximity – logical and consistent arrangement build on the users’ association of interface and content
- Proximity in time – content is available when user wants it
- Proximity in concept – related items are grouped
Proximity builds on the visual working memory which has a spatial component and can remember up to five specific objects.
8. Design for adaptation
If users are frequently using an interface, in the ideal case the interface should adapt itself to the users’ needs or to patterns of interaction. Adaptation is important and allows for different user intentions to be accommodated within one system. It acknowledges, for example the fact that a user can be a beginner or an expert.
As a last resort, include a support source. It should be subtle but easily accessible. Recognize where complexity might demand a little help. Important are the possibility to easily search for a problem and that eventual instructions are represented in a linear form.