As well as developing a business model and target markets, there are other factors to consider, such as rent, utility bills, advertising and staff management, all before you've launched your company.
But help is at hand with Scotland's first business accelerator programme, Entrepreneurial Spark, which has already helped dozens of people develop their start-up companies, providing free facilities and guiding them step-by-step along the way.
In the last of our three articles, LALITA AUGUSTINE talks to two entrepreneurs about how they got their ideas off the ground.
SALLY PORCIANI, 45, from Ayr, is director of Bluebells of Scotland, selling raincoats, hats and accessories for girls aged two to nine.
She is based in the Ayrshire Hatchery, in Dundonald.
WHEN Sally Porciani and her family moved to Ayr from the south-east of England eight years ago, the west coast weather was one thing that took them a while to get used to.
Keeping up with the latest fashion trends with then two-year-old daughter, Emilia, was also important, but the retail store assistant soon began to realise there was a gap in the market for young girls when it came to rainwear.
"Emilia had all these lovely raincoats with Disney and fairy prints, but as she got older she outgrew them," said Sally.
"Teenagers like their designer coats, but I felt there wasn't anything in the middle.
"A couple of times when I would take her to a party, she'd be all dressed up and then we'd put on an old mac over her.
"I felt there wasn't anything pretty for her age group, so I thought I would look into this and take it further."
The mum-of-four started Bluebells of Scotland four years ago, operating the business from home while holding down two part-time jobs.
She sells coats, hats and rain-related accessories made to order through a website and independent stockists.
"I source all my fabrics from London and use local manufacturers to make the raincoats and hats," said Sally.
She went full time with Bluebells, moving to Entrepreneurial Spark's new Ayrshire hub at the Olympic Business Park in Dundonald, when it first opened its doors last month and hasn't looked back.
"Quite a lot of the people here have been working from home in the past, so it's good to be part of something and seeing other people's businesses starting. There's always somebody who can help you," she said.
"When I tell people about this place, it's like it's too good to be true.
"You get all this help from fantastic people who want to help move your business forward – it's a bit like Dragons Den and The Apprentice rolled into one.
"It's a fantastic thing to have your own business. You come up against so many hurdles but if you have passion and believe in your product, you'll get there.
MARK WEIGHTMAN, 27, and STEPHEN STEWART, 26, run
factoring company Integro Property Management from the Gorbals Hatchery
DUO Mark and Stephen first switched on to the world of factoring after becoming home owners in Glasgow, when they moved from Wishaw, South Lanarkshire, to study.
"We had to deal with factors and found it to be a stressful process," said Mark.
"The bills were astronomical, the service was poor and the company's communication skills were very bad.
"We decided to do things differently."
After spending almost a year researching the competition and speaking to other home owners, Entrepreneurial Spark came along when it was time to get Integro off the ground.
"We started trading when we came here," said Mark.
"We had the idea for a company but no contacts or network capabilities. We needed to be put in touch with the right people.
"Being here has been invaluable, having people to bounce ideas off like Jim Duffy.
"When other people believe in your idea, it gives you confidence."
After just six months of trading, Mark and Stephen have almost 60 clients in housing developments across the city, slashing their factoring bills by almost 50%.
"We use local contractors and offer competitive prices for landscaping and cleaning. It's what we would expect in our own homes," said Mark.
"We want to become the number one factoring company in Glasgow and be renowned for our level of service and to be known as the company that cares."
Mark says that if it wasn't for Entrepreneurial Spark, things would have been more difficult starting out.
"If we weren't here, we wouldn't have a company," he said.
"The people we are exposed to and the free facilities, it's all simple stuff that established businesses take for granted, but is so important to us."