I've been working in Government finance for 30 years, including 13 years as a policy civil servant in Whitehall.
There are several ways to reduce public debt - the main three are increased taxation, reduced spending and economic growth. The parties who were talking sense at the election were balancing all three. Labour, the Conservatives and the Lib Dems all produced more or less balanced manifestos that would have worked, although with varying degrees of pain and the length of time taken to reduce the deficit.
The parties who were not talking sense were the ones who either ignored the deficit altogether or who thought that there was only silver bullet, such as economic growth on its own.
Current economic growth in the UK is 0.3% (first quarter 2015, GDP). Even on the most optimistic forecasts for economic growth, there is no way that it will even keep pace with growing pressures on public spending (increased birth rate and an ageing population), let alone reduce the deficit.
Sorry, but the idea that economic growth will reduce the deficit is way out of date.