At Greater Good you can help out with just a click of the mouse. Just click on the button on the top of the page to give to the cause mentioned there. (As I write this it is trying to raise money to build a school for children in Senegal.) Then make sure to click on the tabs for the other causes as well. They will each have their own button for you to push.
If you want to give even more there are plenty of ways you can donate money directly or you can just shop. Choose the site for the cause you would like to help and shop to your heart's content. A portion of the money you spend will go to help out the cause you have chosen.
And if you need a new pair of shoes or a new coat make sure to check out the get one, give one section. With your purchase of one of the selected items they will donate one to someone in need.