7 most important hacks for designing a website for mobile devices
Develop app for each OS specifically. Different operating systems have various properties and it would be better to adopt design properties for each one. It needs more time but you will see the results in a form of the pleased clients. Be sure that this will get you most loyal customers that in the end will be worth the trouble. By the way, in this article you can read more about native mobile application development process.
UI design due to the screen size. Mobile devices have different resolutions and it is the reason to pay attention for the UI design. It has to be available from the different screen sizes without losing the information and main ideas.
UX design for a mobile website. The important point for usability is that a lot of devices have sensor screens. Think about it while evolving design features.