joeymakesmusic The one thing that helped me figure out notes better was to skip the guitar and focus entirely on the bass.
Most bass lines that stick in one's head are melodic in nature (7 Nation Army is a great example of a singable bass line - it's sung at soccer matches!).
For your first "figure it out by ear" attempt - pick something you can sing 'out of your head'. Something so melodic, you just can't forget it. For many these are some form of nursery rhyme.
It's that much easier if it has lyrics - because the natural rhythm of breathing during singing will help getting the timing right.
And if it's a nursery rhyme - highly likely it's using the major scale. Which gives you a framework to find the notes.
For some going the bassline route may help - if your ears are tuned to the lower register. That's where the butt shakes and feet tap, but it takes a little bit to 'hear'/'feel' that register.