I'd say you probably have to work on the english - the grammar really varies in quality. I can tell it's been translated from your native language, and you're doing decently but improving it would definitely make this more readable.
Your art is very skilful - not particularly distinctive as it feels like a lot of artists have this style but you demonstrate clear understanding of your medium and of anatomy. You've done well in that regard.
The story is a bit generic - well executed and endearing of course, but it doesn't grab my attention because I feel like I've read a lot of things similar to it. Perhaps the next concept should be more ambitious. Something that's going to really stick in people's memory.
It also feels like the characters are very simple and follow tropes - you've got a cold protagonist with a short fuse who is rich and entitled, and a ditsy girl who does her best. They're endearing but very simple.
It's a really well executed work - the visual presentation is fantastic. It's the writing that needs work. It's all in how you put the characters and scenes together.
Perhaps your skills are more art focused and you either need to spend some time getting more comfortable with writing or collaborate on your scripts with a co-writer. Hell, I've got pretty formidable writing skill and I know it but even I have a co-writer so that we can help each other keep it interesting.