What you're describing is not abnormal, but it really comes down to two things:

• Firstly, giving yourself lots of time to gauge those relationships (that is, the perpendicular relationships between those lines). Time doesn't fix everything, but it allows us to leverage the best of which we're capable now. It's not at all uncommon for students to limit themselves based on the feeling they're supposed to do things in a certain time frame. Drawabox has no deadlines, no set time frame, and asks only that you give yourself as much time as you need to do every action to the best of your ability, and to make sure you're coming up against your current limitations.

• Secondly, practice. If the issues are so significant and have another underlying issue, that'll come up in your work when you get feedback on it. It's not something you can judge for yourself. It may simply be something that you'll get better at with practice, or maybe there's some underlying other problem that will become clear when the work is submitted, and someone takes a look at it. But until then, you can only focus on the first point - giving it as much time as you require.