Jane Lu built a $30M empire, but there was a huge mistake she made along the way.

Jane Lu has a flourishing business, 155,000 followers on her personal Instagram page and is very much a self-made millionaire.

But for someone whose business has been quite a revelation in the retail and e-commerce sphere, and who is the source of inspiration for women in start-ups across the country, she’s remarkably transparent about her journey to the top.

As the founder of Showpo, the now 30-year-old doesn’t shy away from admitting things weren’t easy, she hasn’t always known the answer, and in fact, her first business had to fail for her second to flourish.

That business is now a $30 million empire.

A post shared by Jane Lu ???? CEO @ Showpo (@thelazyceo) on Sep 27, 2017 at 3:05am PDT

When it comes to business advice, so much of our focus is on everything we should be doing, and everything a founder or CEO ever did right. But rarely do we flip the narrative and ask, what exactly were your big stuff-ups?

“I’ve made several big mistakes, but the one I think other people could learn from the most was not knowing my numbers,” Lu tells Mamamia.

“One December I thought we were killing it because the sales were rolling in at an all-time high. It wasn’t until I actually looked at the numbers and reviewed our margins the following month that I realised that we over-discounted and our cost for acquisition was too high – I should’ve looked at our numbers much sooner!”

Lu admits at first glance, the business appeared to be thriving. And although delving into the numbers isn’t always fun or “sexy”, it is “crucial”.

It was a mistake that, plain and simply, couldn’t be fixed. The company couldn’t recover the money they had lost, so instead, they just looked forward. How could they prevent something similar from happening again?

Naomi Simson on how she built Red Balloon. Post continues after audio.

“We definitely worked extra hard over the next few months to make up for the sh*t December – generally December is a great month for sales, like most retail businesses – and I’ve put a bunch of processes in place to ensure it doesn’t happen again. Namely [the biggest lesson I learnt is] just checking the bloody numbers,” she says.

It was this horror month that taught the entrepreneur to “let numbers drive [her] decisions”.

“You can’t let your personal opinion make decisions for you, you need to base it on numbers. Of course, your intuition and gut feeling is important, but you need be careful that you’re not just rationalising because you’re hoping for a certain result, but rather you can make a sound business decision based on your gut that’s backed up by numbers.

“I always check numbers now. I look at our sales daily, our stock expenses weekly and overhead costs monthly. And I constantly review it comparing with the prior month, the prior year and keep an eye on key ratios.”

It’s particularly niche advice, but a theme that’s fairly universal for anyone going into business: don’t be complacent.

It might just be your biggest downfall.