Legend title should be superior to the legend labels. The easiest way is to make the title in all caps, leaving the labels in upper and lower case. This is easier than changing fonts. Go to the View, Theme Properties, and retype the title in capital letters. Because of the dynamic link between the View and the Layout, the legend will change automatically even if you make those changes late into the map composition process.
Labels normally have a capital first letter.
Legend titles should not be redundant to the map title. Also, they should not be wordy and usually should follow the grammar rules mentioned for the title. Make the title descriptive. When possible, the labels should be aligned with the classification boxes through a horizontal center. Be careful - sometimes the recognized space for the letters includes an invisible portion above, resulting in the labels center being higher than the letter center.