There are a number of “strong selling points” needed in the first chapter to make the manga memorable.
If it’s a character driven manga, then we need to establish their unique characteristics from the start. If it’s the start of an epic story, then it needs to inspire. Similarly, it it’s an erotic manga, we need to eroticism!
Including all these points into the first chapter may be a difficult task for beginners, but if you recognize ONE element that makes you think “I’ve got it!”, then please add it in.
When looking at a serialized manga, the final scene in the opening chapter should leave the reader wanting more. In a character driven manga, we want the read to think “I want to know more about this person”, or a story driven manga… “What happens next!”.
Ultimately, giving your reader a strong emotional response is the test of a successful first chapter.