What you drew looks fine to me in terms of form. Your linework is not very interesting, but that comes with experience.
Take a close look at your study: >>63690
The lines aren't straight, they're curving. The chest is denoted with a faint c-curve that loops back into itself at the top.
The lines are also applied rapidly. On the right we see a folium with a line underneath it. These feel like a single line, even though there is a clear break on closer inspection.
The lines are applied with a feeling and idea of how it all goes together. This shows in the final product.
There's a lot more going on, but this should get you started.
Unfortunately, this is something that is harder to pick up than anatomy, so I'm going to refer to >>63683
's advice even though I don't agree with it. In any case, just drawing more is the way to go here.
Construction is optional (and slow). Not to mention that, in your own attempt, you change the figure to something that is entirely different than initially presented.
Tomo's issue stems from control, not anatomy.
Cuddleslut is great!