Deciding on where to apply is really important; hopefully you are going to be there for at least five years! When trying to decide there are a few important things to look for. However, it is also worth noting that all medical schools have to follow the GMC's "Tomorrow's Doctors" and ALL will meet the standard to become a future doctor.
It is worth looking at what weighting each school gives to parts of your application. If your UKCAT score wasn't great but you've got really strong GCSE's then apply to medical schools that put less weighting on the UKCAT. Make sure that your GCSE and A Level's will meet the basic requirements of the programme you're applying for. A surprising number of applications will miss this and that means instant rejection. If the UKCAT didn't go well then question if the BMAT is worth doing?
Are you looking forward to a traditional lecture theatre and a good scientific grounding, or are you a more individual and self-driven learner? It is important to figure out how you learn best and apply to schools that will meet this requirement. More and more medical schools are putting clinical "experiences" in the first two years but if you're desperate to get into the clinical setting then apply with this focus. Are you desperate to dissect? Many do full cadaveric dissection, but you might also find that you learn just as easily with prosection. Make sure that you are aware of opportunities to intercalate.
A New Home:
Five years in a new place is a long time, and like it or not your university town becomes a new home. It is important to consider how easily you can get back to your family and friends. Look at how easy the transport is, could you pop home for a weekend? You should also account for living five years in a new place. Some cities are more expensive than others, how much can you afford to spend on accomodation and living? Look at if the university is a city or a campus, each will have a unique flavour and it's important to feel happy in your surroundings.
Write a list of universities that you feel might be for you and then go to a few open days. You can really get a feel for somewhere by visiting and you also get the chance to ask some important questions about the universities and meet some other aspiring medics as well as current ones.
Wherever you end up training, most tend to really enjoy their five years and a lot of people will continue living in the same area. It's worth saying that despite differences in location and learning style everyone will come out with a Bachelors in Medicine and Surgery and be ready to walk into the medical world.