As a Euro-sceptic I have been sitting on the fence. However, the 'debate' amongst our political leaders hasn't helped, and seems to have degenerated into 'project fear' versus 'project lies'.
From what I've observed there are two main threads going on, and your primary concern may determine how you vote. Those whose main concern is about trade and the economy seem to favour 'remain', and those whose main concern is about the free movement of people and migration seem to favour 'leave'.
During the referendum campaign I've found some interesting statistical information. One is that "Germany and Britain have historically been the largest contributors to the EU. On a per capita basis Britain is now the eighth largest contributor to the EU (behind the Netherlands, Sweden, Germany, Denmark, Finland, Austria and France)." https://inews.co.uk/essentials/news/uk/much-pay-european-union-facts/.
The second is: Which type of person wants to leave, and which type wants to remain? You Gov recently conducted a poll looking at, amongst other things, the affect of age, education, and social class on EU support (I really should be a pro-Europe enthusiast!). http://www.telegraph.co.uk/news/2016/03/21/eu-referendum-who-in-britain-wants-to-leave-and-who-wants-to-rem/
My greatest concern is the long term impact on the UK economy and how new trade agreements would develop in a revised political landscape. As such I've decided to jump down on the 'remain' side, although a 'leave' result would be more politically interesting!
We'll see.
Whatever you think, please vote.