I can give you the standard answer, brand, audience, marketing and half a dozen other things. You can spend thousands on any or all of those three things but if you don't grind, get better all the time and learn. You've wasted your money and time.
The reality is just grinding away every day. 14-15 hours a day 6-7 days a week, not for a month, a year, 2 years... whatever it takes. Never say die attitude.
Whilst our competitors are on holidays or just slacking off. We're still working stealing their customers. If you don't keep grinding away you'll never succeed. Of course just grinding away isn't enough.
2. Continuous improvement
Never settling, learning from mistakes, recovering from it and just keep grinding away. Just focus on just getting better all the time.
What has made us successful, (4x) was just getting better. Better at knowing our customers, better at producing the product. Better at communicating with our audience. Better at customer service, better at everything that matters to our industry, our market.
3. Finally, it's self-education. Being open minded to new knowledge. Learning from others, learning from customers, learning from competitors. Learning from successful entrepreneurs in other industries. Constantly learning new skills and learning to be a better entrepreneur.
If you really want to succeed. Grind, work on getting better and keep learning. Everything else may be helpful but if you don't do these three things you are relying on luck.