Adding leavening agents like baking soda and cream of tartar helps create air pockets in the dough which gives the texture a fluffier feel. If you're not sure about measurements, then stick to one teaspoon each for both; just remember that too much baking powder or soda can have the opposite effect by making your banana bread dryer instead of fluffier! Be careful not to mix these ingredients too vigorously because that could eliminate some of their aerating power – just gently fold them into your batter until everything else has been combined well enough, so no lumps remain visible on its surface before putting it into an oven preheated at 350 degrees Fahrenheit (177 Celsius) for about 45 minutes until golden brown around edges & top looks set when lightly pressed down with fingertip (or toothpick inserted into the center comes out clean). Remove from oven & let cool on a cooling rack before slicing & serving warm, slathered generously with butter! Enjoy :)