Sola told me about this video, I liked it. It gives you more to do if you’ve ever thought you’ve run out of things to practice.
Playing in thirds means you play a note and go up (or down) a third. If you’re in minor, you use the minor scale’s notes.
Two up and two down means you play the first note of the scale and a third up then the second note the scale and a third up then you play the third note of the scale and play a third down and then the fourth note of the scale and a third down.