Here are Heinlein's rules (or as close to them as I remember) and how I've broken them.
1. You must write.
When I first started writing, I did everything but actually write. I thought about it, talked about it and read about it.
2. You must finish what your write.
On those rare occasions I actually put pen to paper (or fingers to keyboard) I would get a few hundred words in and fizzle out. Writing came harder to me than I thought it should. Frankly, I felt entitled to become good at it without practicing.
3. You must not rewrite unless to editorial demand.
I broke this rule every chance I got. My writing dripped out of the faucet. Then, the few words I managed to compile would be rewritten again and again. I wouldn't even wait to finish the story, since I was breaking rule 3. I'd rewrite each sentence and paragraph until no life remained in them.
4. You must put your writing on the market.
Only a small percentage, maybe 10%, became submissions. Not a recipe for success.
5) You must keep it on the market until someone buys it.
The vast majority of that 10% was rejected, and rightly so. Some of it I resubmitted elsewhere, but not consistently. Furthermore, I wouldn't write while waiting. I was too busy waiting to receive my rejections.
There. The formula for failure as a writer. Now go do the opposite. Heinlein knew what he was talking about.