I'm more worried about what we aren't being told by each side than what we are at the moment. comments made by the USA (or it's representative at present, Mr Obama) to the end that the UK would be at the bottom of the pile for trade agreements is worrying (yet it was a one liner on the news before getting back to the important stuff like who's banging who in what way), whilst they aren't a major market share for us as such they are still one of the major players in the international market and can drive it to their will. EU has trade agreements with them ( and other non EU countries which we are unlikely to be able to reach agreement with outside of the EU). we leave, and we lose some of that safety. it keeps being screamed that we are not a manufacturing country anymore, this is true for the most part, we do not produce heavy industry like we used to, but we do still manufacture, very high tech and very specific equipment that is sold around the globe, without EU backing this is likely to become harder. i the modern globilised market we can not stand alone, it's insane to believe we can, we are a small nation with limited resource, most of which we have sold off in short sighted money grabbing ways.
the same thing that Scotland touted in their bid for freedom is being spouted for the UK, we can be like Norway, a non EU member who has trade agreements. how many years do you think it took for them to achieve this? why do you think they managed it (hint, because they've got a shed load of gas and oil and don't really use it), do you believe we have the same assets to sell (no we do not) and do you think they aren't having to follow the same laws you are trying to escape by leaving the EU in order to sell there? (another hint, yep they do and they get absolutely no say in what laws they have to follow to do this, they don't follow it, they don't sell to the EU).
do we have power in the EU? yes we do, we have 13% of votes, but it isn't that simple, we have members on the committee which vote for certain important things, but that isn't quite so straight forward either, you want to know more go research it.
Leaving the EU will cost us, there is not really a debate about that, the problem is how much it will cost us, something that's impossible to say. it will cost us to stay as well, but is that cost more than leaving? again, not possible to say, but from all external sources it looks like we will be worse if we leave.
I guess the real issue is that it's impossible to be impartial in the UK on this subject, outside guidance is needed but isn't forthcoming. I'm on the stay side, but only just and can't really put my finger on the detail enough to push me either way.
oh and only site I've found so far that has a fairly unbiased view is
https://fullfact.org/europe/
this isn't to say that it's not biased, it is to say that it's the only one I've found that doesn't look to be biased.
good luck, I hope the media frenzy dies down and we actually get truthful and easy to understand information that allows us to vote the right way.