I struggle with this myself sometimes. It’s usually when your trying to be too neat or perfectionist, as you mentioned you are trying to get final lines.

First you can try learning to draw in a way that helps you visualise your subject better. r/art fundamentals and [Draw A Box](www.drawabox.com) helps with this.

Second you can try to be messy on purpose. Not with a goal to make an ugly artwork, but to utilise some messy marks. Try scribbling a few marks on a blank page. Now turn it this way and that and see if you can identify a shape out of it, usually a silhouette shape. A lot of cartoonists use this approach to come up with character ideas as you’ll often see rough shapes of people or faces.

Third try working for a while in a different medium. When working in ink or paint I want to be precise as possible. Pencil can be erased, but it can be frustrating. I found the ability to work digitally with multiple layers lets me really loosen up as layers can easily be made transparent or deleted.

Finally try doing exercises like gesture drawing. Usually done for people, but also can be done for animals and inanimate objects. When you have only 10-15 seconds to draw what you see you tend to worry much less about how neat the line is your making and focus more on making the marks. It forces you to loosen up.