Use safety scissors to cut along a thick, straight drawn line.
Snipping made little cuts. Now you will make one long cut, all the way down a line.
Open, close, open, close. Follow the fat line with your scissors from one end to the other.
Mastery looks like: They cut along a straight line from end to end, staying reasonably close to it.
Common stumbles: Making one big cut with wide-open scissors instead of several small snips in a row.