A large number of Country and Country Rock songs have an underlying rhythm of constant eighth notes, often played by the drummer on the hi-hat cymbals or the ride cymbal.
Any other member of the band can create a part based on eighth notes and instantly connect with what the drummer is playing. To play solo piano it is very important to have control of all rhythms because there is nobody else to keep time for you. Here are some eighth note studies to help you gain control of different placements of eighth notes within a bar.