Here is a chart with common types of suicide and the rates of them
As you can see, using firearms (guns and etc.) is the most widely used for suiciding. After that comes suffocating, poisoning, and etc.
Here is a graph with the statistics of suicides in genders/ethnicities
As you can see, males are more likely too suicide by quite a bit, and American Indian/Alaskan Natives are most likely to suicide, too.