Quality content means adding value to your readership and audience. Not every article you publish has to be 1500 words long but make sure you are focusing on writing good quality content.
1. Spelling - Besides acronyms and slang you should make sure all words are spelled correctly.
2. Grammar - This one is tricky because not all software arranges words the same way. Just keep it simple so people can read and understand what you write. If you struggle with grammar write shorter sentences until you improve.
3. VALUE - If your readers are not receiving value from your content they will lose interest. Make sure you stay on topic and give helpful suggestions when you sharing a article. Not everyone will love your niche and ideas so don't be discouraged to write about what you love! That is how you will create value, if you have passion for your niche it will reflect through your content.