While it's not inherently an issue, you might want to reflect upon your reasoning. I can see plenty of reasons not to want to use hatching - it can be quite time consuming to execute those individual lines with care, so one might look for an alternative. But even in applying an alternative like filling the plane in with a marker, you still need to employ some care - and I can see that your execution there definitely spills over the lines defining that plane. I can also see that you're going back over lines repeatedly in a manner that looks like you're either attempting to correct mistakes, or without as much care as you could. Always be sure to apply the ghosting method in its entirety, taking as much time as you require to plan out each stroke and ghost through the motion of its execution, before finally committing to a singular stroke, with confidence. Don't hesitate, and don't go back over the line in order to correct it.

And of course, this applies to the application of line weight as well - use the ghosting method.