2:04 PM, Friday September 18th 2020
Regarding the intersections, yes it definitely has to do with looking flat because you applied too much, but I'm glad te hear that you are trying to apply your new knowledge!
Now, Don't feel afraid to make line, remember what Comfy says all the time, we are not here to make pretty pictures, we are here to learn, so what place better to give your best and learn from your mistakes? And on the same note, your mistakes will be the ones that teach the most, so don't avoid them, embrace them.
One last thing, I've noticed you said that you went on to lesson 4, so I checked your sketchbook and it seems that you moved on without waiting for a critique on your lesson 3. Don't do this, I'm telling you for your best interests, what makes Draw a Box so good it's the fact that someone else gives you feedback so you don't drag your mistakes from previous lessons. Just think about what just happened, You are now using the advice I told you from lesson 2, on lesson 4. If you would've waited you would have gotten over that in lesson 3, and someone would tell you another thing that you could improve on in lesson 4. So yeah, be patient, don't try to rush learning!