Your personality

No one appreciates a rude writer. Readers like to feel that their opinions do matter, and with the wattpad feature of comments you can reach people's point of views, you have to manage to listen to their requests politely and doing your best to satisfy them since a writer is literally nothing without their fans

Watch your grammar

Readers do pay so much attention to the grammar being used, no one likes reading a book full of grammar mistakes making it harder to understand, it also gives it a feeling that it's a nonprofessional book, written by some kid and so it doesn't deserve to be read. 

Vocabulary

Vocabulary is one of the main assets that has to be taken good care of while writing, it is so boring to read a book full of the same words being repeated over and over again! Your book has to be rich with different nouns, verbs, adjectives and adverbs so that the readers would be able to feel the situations you are writing

Be realistic

Unless the genre you are following is fantasy/sci fic/ horror, you have to be realistic. We all know how pissing off it is to read a book full of unrealistic moments, like; my crush fell on top of me our lips accidentally crashed. I honestly find these kind of books pathetic! You have to be realistic.

Avoid racist language.

I already think that racists are sick, but apart from that.

Wattpad is connecting people from all around the world, so if you use racists language, it is probably going to cause a huge loss of readers since you probably might be racisming them.

No making fun of gays, lesbians, arabs, asians, religions, black, white, #NORACISM at all.

If you are describing any of these cases, you have to make sure readers aren't feeling any racism in your writing at all.