@anonboi2000 Hi there, unlike Catalin (previous writer) I haven't been writing on my own that much, I just helped him out whenever he needed it.
For starters I suggest to brainstorm ideas and very importantly, to note them down, personally I use notepad. As you know hitting writer's block is quite common, you can combat this by reading other stories, playing games or watching shows. Ideas can spark up when you least expect it.
For example, recently I have played God Of War: Ragnarok, during some segments of the game it gave me ideas regarding combat. The norns, I really liked how they're written in the game... it gave me an idea for making a similar character in the future so my story can have an interesting twist.
Something that's also quite important to learn is how to handle criticism, if you can't handle it well it's a recipe for disaster, you're probably aware of the current situation with KSI... don't be like him. Instead learn the criticism to your own advantage, usually people point out your mistakes in story crafting, learn how to improve upon these mistakes. You can even ask them for a more detailed critique, don't be shy/afraid of communicating.
Something else I suggest is to just have fun writing, you don't have to follow big trends to become popular, however here on Wattpad from what I've seen Fanfiction and Romance are kings, so start with these genres. I don't suggest horror since from my experience it needs to be quite complex, you have to play with the reader's mind in order to spark that horror element, you know what I mean?.
That's pretty much all the main tips I can give, sure I can go more in depth but that would take too much time.
I also apologize for responding late, I hope this message found you well.
Have a good day, and happy writing!