A great question!
1) Outlines make life easier. Even a skeleton outline will help you keep track of everything you've written. I learned quickly you won't remember everything.
2) The amount of words you write in a day doesn't determine how good of a writer you are. Some writers can pop out 5k a day like it's nothing and other may only write 900. Both are ok. Do what's best for you. Rushing will hurt the quality of your work
3) This a personal thing: World building matters, knowing your characters matter. Spend time on both. It can make all the difference in capturing your readers.
4) This is something I generally tell any writer. Be open to constructive criticism. You will never get better if you are resistant to advice. That being said, everyone will have different opinions and criticism. Don't bend to every bit of it. Take an honest look at your work and decide on what you can improve on.
5) You can't please everyone so don't try to. Not every single person who reads your work will like it and that's ok.
6) Focus on improving your craft, not popularity. Not many people get famous instantly and really, it's not a race.
7) Practice different genres and styles of writing! It may help you find your own voice and improve your writing skills.
Hope that's helpful!