Start with any buttons you may have at home. While it is unlikely that you will find anything of major value, you may get an idea for the type of buttons you would like to collect (a specific color, a material such as glass, wood or Bakelite, a particular shape or a certain image, such as animals). For help on this visit the Button Collecting website (see Resources below).
Check Internet button display sites such as the National Button Society website to see what types of buttons are plentiful or rare and what they cost (see Resources below). Use the facts you find to help you decide on "your" buttons.
Continue your research with books found at the library, local bookstore or at the A Button Collector's Book List website (see Resources below).
Collect Buttons Everywhere: if you go to the charity shops and boot fares, you can get a tin full for a few pence.
Make sure that the type of button you have chosen is easily available. If not, expand your category to include other materials, historical periods or themes.
Start attending live button shows held every year in most places, look them up on google and contacting other collectors near you. If you are interested in modern buttons, you may find something that suits you at your local fabric and craft store.