Manga hair

The most iconic way to make your character stand out from the rest is  to create a unique hairstyle for them- But because it is the best way, it's also the most USED way- so instead of just one 'unique' cowlick or ponytail, you can use create several different cowlicks or what-have-you and combine them to create something that hasn't been seen 12 hundred times before.

A thought just popped into my head, that your character doesn't have to be super unique, just unique in your world. Your character doesn't have to  be the only blond-vampire-with-a-ponytail in the anime world, but maybe they're the only one in your manga.

A young artist I know always draws his girls with long hair and boys with short hair. There is no other difference. Same spikiness, same volume. FINALLY he asked me what he could do to differentiate the genders since their hair all looked the same.

According to this handy chart I've made above,

1) Girls' hair is more voluminous and bouncy, and even when it's short it has a fuller look.

2) Guys' hair is generally coarser, or spikier. When it's long, keep it thin to differentiate your guy from your girl characters.