If you want to make your playing sound jazzier or hipper, simply substitute a Major 7th chord for any Major chords. For example if in the song you are supposed to play a C chord, substitute a C Maj 7 instead. It will sound like this. So if you were supposed to play an F chord, substitute a F Maj 7 chord instead. It makes things sound a little more modern or jazzy. There are a few times that this substitution won’t work, but you will be able to tell right away. It will sound very wrong or dissonant. Again, this is an easy way to quickly make your playing sound more jazzy or hip—simply substitute a Major 7th chord for any Major chords.