Sometimes, money tells you what to buy. Samsung has provided various phone with various price.
2. Choose Operating System (OS)
Fact has shown that Android and iOS has become the primary OS in every smartphone. It is better if you made careful observation and research about all the OS in the market in terms of functionality and its capability.
You are advised to choose smartphone that has at least dual core processor. Research has shown dual core processor is better than single core in term of life expectancy.
Try holding the phone. It is the best way to feel it. If you are confident enough, try putting it in your pocket but make sure you did not walk out from the shop with the phone inside your pocket.I mean, don't steal it.
Most of the smartphone has large battery capacity but cannot hold longer because it is not suitable with the phone itself. The best way is to ask the sellers.
The best screen technology is from AMOLED or LCD. Take note with the screen resolution. Choose at least 800 x 480px screen for better experience.
It depend on you. Take some picture using the smartphone that you want to buy. Don't just listen from the sellers.