These important tips help you buying new phone.RAM-See how much the ram does you phone have if ram is more like 2gb or 3gb so your is superfast. So check RAM of the mobile.PROCESSOR-processor is that run your device and give speed and boost up speed so please check the processor also.TOUCH-please check also the touch of mobile for it might be misbehaving so check also touchCAMERA-camera is reqiurement of all person.so it is also usefull you.so check also camera quality.
Please also chech battery backup