The first is to pick an indentation style indenting between 2-4 spaces, and then start using it. Now. Running your code through perltidy will show you what it looks like.
The second is to call functions with explicit parameters. That means using parens. As documented in perlsub, if you use just the plain & and in a function you call another function, that other function will get the parameters to the first as arguments.
Believe me. You may think these are picky details. But they are not. The first strongly impacts how easy it is to pick out your logic at a glance. The second is causing a subtle set of side-effects that may or may not be intended which a maintainance programmer may or may not know enough to notice.