One of the most effective ways to restore your faith in humanity is to start spending more time among people who are less fortunate or under-privileged as compared to you. Witnessing what they are experiencing and how they are managing to cope with it without complaining or losing hope will make you feel proud of them and humanity in general. If you want to get involved with them and observe them even more closely, volunteer to help them in whatever way you can. Do not just read about them, go and mix with them.
Rather than talking about problems, talk about more positive things with others. Ask them to share their happiest moments and memories with you. Learn about the incidents and people that made them happy and inspired them. Everyone has someone they look up to for guidance or inspiration. After giving the person enough space, he or she would gladly open up to you about the happiest memories and inspirations.
You may have been getting exposed to the dark side of humanity for some time, which would have caused your faith in it shatter. However, try recalling things that people have done for you in the past. These things can be something really big like rushing you to the hospital in case you were in a car accident or lending you money to get back home in case you lost your wallet, or relatively smaller things such as allowing you to have their seat on the bus or slowing down their car to let you into the lane. Remembering these gestures of respect and compassion are sure to play a role in restoring your faith in humanity.
There is a lot of negative news on television and Internet these days. However, you do not necessarily have to read such news stories. Instead, try to find stories focusing on virtue, kindness and heroism. Everyday a lot of people do something great for someone else, though these acts go unnoticed due to a depressing and more sensational news story. Read about the positivity in people instead of the negativity, which unfortunately gets more attention.
Learn to have a more optimistic view of the world. Give without expecting anything back. Your actions will allow you to fill up with compassion and soon you will notice others getting inspired by your acts of kindness, virtue and compassion.