The notion that UKIP lost the election for the Conservatives is erroneous.
UKIP cater for a niche of voters who would otherwise (mostly) vote Conservative. However, a mainstream party cannot cater for all tastes. If the Tories became more euro-sceptic to squeeze the UKIP vote, they would most probably have lost more votes to the Lib-Dems and Labour. Any main-stream political party must be a broad church. The problem with our current political opinion is that we had two left-of-centre parties that got over 50% of the vote, a mainstream right-of-centre party that got 36% of the vote and UKIP that got 3%.
The conclusion for the Conservatives is not to try to appeal to a very broad church by merging many different opinions. Rather, they must capture a vision that people can empathise with, as did New Labour and Thatcherism. The time to introduce this was not with the launch of the manifesto, but two or three years before an election. Further that vision should also be an implicit attack on the alternatives.
A positive vision to vote for; and the opposing failures to vote against.