As either a developer or a tester, you have to know develop process. Different companies probably use different develop mode, e.g. Waterfall mode,V mode, Agile mode,etc. Whatever mode used in your company, product lifecycle is the same.
Based on product lifecycle, here's the process for testing mobile application product. It's summarized from my practice in testing different kinds of mobile apps(native,web,hybrid).In different phase, it's better to do different things. If you haven't finished preparation or have a too-simple prepartion in the initial phase,you will spend more time once testing's started.
A journey of one thousand miles begins with one step.Preparing and planning is the most important step.