When aspiring entrepreneurs ask Nic Brisbourne for tips on fundraising, the managing partner of Forward Partners cites a conversation he had years ago with Rikki Tahta, who was looking for early funding support for Covestor, his US-based peer-to-peer investment platform.

Rather than pitching his business as the "Uber for finance" - which Mr Brisbourne hears frequently now and grumbles is a linking of ideas that is a particular turn-off for VCs - Mr Tahta asked directly what he had to do to get Mr Brisbourne's backing.

"I'd never had an entrepreneur try to close on me like that," Mr Brisbourne recalls. "It was very effective in teasing out the steps to getting an offer, what he could do to help and the chances of getting there."

Britain's fundraising market is becoming competitive. The amount of early stage investment in UK companies by members of the British Private Equity & Venture Capital Association (BVCA) fell from £126m in 2015 to £112m last year. The number of companies receiving such funding also fell from 179 to 145 over the same period. The average investment, however, went up from £704,000 to £772,000.

The BVCA does not record the failure rate from the hundreds of pitches a VC will receive each year but it estimates that only 10 per cent of those submitted result in a face-to-face meeting and barely 10 per cent of those will win funding.

Mistakes in pitches that lead to bids being rejected are "almost too numerous to mention", according to Mr Brisbourne.

Dale Murray co-founded Omega Logic, a pioneer in mobile phone credit top-ups in the UK, before turning to angel investing. Her main advice for those pitching for early stage funds is to be open about gaps in your business plan. "You don't have to know everything, but you do have to build trust with your investors," she explains.

The "particularly clever" pitches come from people who have researched their target investor and can tell potential backers what business skills they might add to the business in addition to money, Ms Murray adds. Robin Klein, general partner at LocalGlobe, a VC firm for early stage companies, is put off by pitches that aim to sell the business within five years. "It shows the wrong ambition," he says.

A founder's ability to explain their potential is as important as the company they are pitching, Mr Klein adds. "We love people who have done a lot with very little," he says. "These are people who are likely to be as careful with your money as they are with their own."

One founder won LocalGlobe's backing for the sole reason that he had convinced 20 PhD graduates to work for him on little more than the promise of future equity.

Mr Klein admits that back then he struggled to understand the technology the company was using, but he was persuaded that the founder's leadership talents were worth backing.

"It was a real tribute to his ability to sell a vision," Mr Klein says. "On that alone we made an investment and it turned out to be a spectacular investment."

A good pitch shows that the founders have something to lose if the venture fails, according to David Giampaolo, chief executive of Pi Capital, a London-based investor club. "They need to show skin in the game," he says.

It is important not to oversell the upside, Mr Giampaolo adds. "Warning bells go off when people talk about 10 or 20 times your money back on the investment."

Eileen Burbidge, a partner at Passion Capital, warns against pitching to too many potential investors.

"Don't cast the net too wide," she says, noting that VC firms become wise to people "spamming" their presentations. Fundraising is a "people business", she adds, and you do not want to annoy backers.

"Save your and their time," Ms Burbidge adds. "You never know when you might ask for it again."