The goal is to make user"s interaction with your website as simple and efficient as possible without unnecessary distractions.
Here are 10 fundamentals of User Interface design that you should bear in mind.
1=> Stay out of the way
This essentially means that help users achieve their goals effortlessly. Do not distract them with unnecessary options. Keep your design intuitive and straightforward.
2=> Understand Users, Don"t Obsess Over Competition
Trends are changing. Don"t obsess over competitors "" instead obsess over your customer"s needs. Research well "" understand what kind of interfaces work and what don"t. Ensure that your interface is directed towards ease of use for a customer. It"s best not to get carried away by what your competitors are doing.
3=>Familiar Patterns are good, help users feel at home
Users are generally familiar with well known patterns and designs. The most common interfaces they use on a daily basis are google"s mail, Facebook, Twitter or Blogger, A popular banking site or MySpace etc. You need not create something wildly out of the way. Users love familiar patterns that they can easily learn.
4=> Stay Consistent
Your design consistency will help customers feel more in control and this will make them like it all the more. A consistent interface makes users more comfortable and hence is good for your website/software. Layout and design are some of the elements that require consistency.
5=> Use Visual Hierarchy
Maintain a hierarchy in your design "" always. Users will quickly catch the steps in the navigation and know how to reach what they want. Don"t make them look around too much! Maintaining a hierarchy will prove beneficial for your website too, as it reduces the clutter in design. It also greatly reduces the complexity in design.
6=> Provide Feedback
Make your user interface design speak to the user. It should provide feedback whenever a user did something wrong or right. Inform users of their actions and their repercussions. Give them the right option too.
7=> User Error Tolerance
Users are bound to mis-click. Make sure your interface design has tolerance for user errors. Users should be able to "undo" actions or re-enter a wrong input. Your design should show what went wrong and how it can be fixed.
8=> Simplicity is cool
Simplicity is the new cool. Your interface need not have unnecessary elements that are flashy or unnecessarily animated. Always ask yourself whether it is appropriate or does it fit the theme or logic of the underlying function. Don"t avoid animations completely "" they are great when used appropriately.
9=> Keep moving forward
Always do a little homework about the recent and upcoming trends and do not hesitate to re-iterate your user interface.

10=> Make things easy to understand for user
Keep your interface more and more conversational. Make labels very direct, make the messages easy to understand and provide options to users to select the right one.
Making your user interface as intuitive and easy to use is the key to a great design!