My number one writing tip is: DON'T keep going back to the beginning and fiddling with stuff and starting over. You are allowed to rewrite what you wrote the day before but touch NOTHING you wrote before that.
I have met people who never finish anything because they keep starting over and over.
Number 2: As you go along you will realise there are changes that you have to make in what you have already written. Don't make them. Just start a folder called "Things that have to be changed", note it there and once you have written the whole thing you are allowed to open the folder and rewrite.
Number 3: When writing the first draft, don't worry about what potential readers will think about it. Don't worry that they will be offended by something or that they will interpret something in a way that you don't want them to. DON'T think about how the work will be received. You do that in edits.
Number 4 might be personal and work only for me: Write a scene and get what you think is most important in there. Then the next day you read it over and add details. Smells, facial expressions, weather, taste of the food, passersby etc. Then you don't touch it again until the draft is done.
Number 6: It can sometimes be good to have many beta readers. Sometimes I will let 5-7 people read and then I only change the stuff that 3 or more say I need to change.
Number 7: It can also be good to only have 1-2 beta readers. But then they have to be readers that you really trust and you know their taste and they know you as a writer. It will take time to find those readers, even years. But once you do you have to treat them very nicely and buy them many beers.