Slow charging is a very diddly problem, though every phone has a battery life, there are some tricks that can help you deal with bad charging times.
Whenever you get difficult charging times, your first step should be to restart your phone. Restarting any device really take you out from any technical complexes.
If you really want to enhance your charging speed than you need to close all application while charging. Social application like Instagram, twitter eats a lot of battery.
The most important thing you need to do is to clean your charging ports on daily basis as the dust gets entangled between charging ports that causes slow charging, blowing a little air on the port can remove the blockage. These tips will surely amplify charging speed.