Fields

Private fields have the _ prefix, static, const and public fields are in UpperCamelCase.

For example:

public class MyClass 
{
    public int PublicField;
    private int _packagePrivate;
    private int _myPrivate;
    protected int _myProtected;
}

BAD:

private int myPrivateVariable

GOOD:

private int _myPrivateVariable

Field Position

All fields should be at the top of the class, before any methods.