Honestly, i'll +rep the **** out of anyone who types out the lengthy reply that question requires. Have you been to see someone at university about your options or had a good look around online? Check out wikepedia, Big 4 careers websites, financial companies careers sites, efinancial careers etc. I believe KPMG and Deutsche Bank (if my memory is right) have some sort of online quiz that helps explain where people can fit in.
To put it in very basic terms, any job in finance is quite technical. You should expect to be very computer literate, good with MS Office packages at the very least, and a confident communicator. Those are just starting points, some roles will expect more maths/computer literacy than others, and some will require better communication/people skills or even a high concentration of both.
Investment Banking/corporate finance is good to get into, potential for earning is very high but it is hard to break into, can be stressful and you will be hated by the general public. It is a ruthless sector driven by results, it rewards high performers and drops dead weight pretty quickly. Arguably, once you go into banking, especially front office, you kind of have to stay within banking or similar fields. I don't know much personally but I imagine it would be near impossible to go from trading bonds to working in Finance at Selfridges for example. Retail banking is very different to what i'm talking about here though and is in a completely different ball park so don't get the two confused.
Retail banking is ok, it isn't a bad career by any means but, most people in the know will laugh at you if you call yourself a "banker" and peddle mortgages to average Joe public.
Accountancy probably opens more doors and allows more freedom of movement but don't expect the same salaries/bonuses as banking. It's not impossible to earn similar amounts, but it's not easy either.
There are literally hundreds of jobs that you could go into with your Economics degree, I've barely even scratched the surface with my explanations. It all depends on what your are like as a person and candidate. Your best bet is to do some more research online and then come back with some more specific questions then start looking towards securing some work experience. You should go along to more career events at your university, i'm sure the companies there would love to explain these things to you and hand out all sorts of free junk.
Great, I ended up being the person typing up a lengthy reply