Start with the people closest to you.
There is a mentality about helping others that is lost to those who try. Why are you doing it is the first question you must answer to yourself. If you have an agenda you can do more harm than good.
Never expect anything back for helping others. In fact just the opposite happens a lot. You turn out to be the bad guy in their mind and people turn on you blaming you for their problems. Most people never see that the fault lies within themselves and are always looking for scapegoats. Most people want to be told what they want to hear not the truth.
The best way to help people is to be there for them when they need a friend. Only do what they ask. Most people just need someone to talk to, not with.
Things like volunteering in a soup kitchen or something like that or a children's hospital is great.
Never expect a thank you or anything, do it for your own soul. If you expect a pat on the back, forget it. The reward is personal between you and yourself.