So visually: it’s a lot more important than you may think! The story has to look visually good for the reader to fully enjoy it (there are great stories without much visually interesting things), you should do zooms! They really help intensify the mood and dialogue. Also a thing I’ve noticed, is that the speech bubbles have to look good too! Proper spelling, grammar, and also a space after a comma. Use some overlays and layering to add depth to the story!
Tips for an interesting plot/story overall: don’t overthink everything, write what you like but feel free to take suggestion from other people, don’t feel pressured to write if you don’t want to! To keep the story interesting, don’t reveal everything about the characters at once! Do some flashbacks (but not too many, it can get quite annoying), do cliffhangers, ask the reader questions and only later give the answers, keep the reader wondering and imagining what could happen next. Do plot twists, if a reader thinks they know what’s going to happen, prove them wrong!
It also really helps if you have planned out what you want to write beforehand.
I really hope this can somehow help you!
Best of luck in writing! 