Forget OTG Cable here comes Micro USB OTG Adapter. Easy to carry, small and handy. it can be used with any Android smartphone that supports OTG function. This is compatible with most android smartphones and tablets that support OTG function.
With this you can easily use a USB Pendrive to transfer the files, music and videos or you can directly play them from pendrive thus increasing the storage capacity of your phone. Also you can attach a mouse to the OTG adapter and play your games and do anything you wish. A keyboard can also be attached if you need to do a lot of typing work.
Please note that using all these accessories with your smartphone consume battery from so make sure ou have a power source close to you.