The location of your premises is incredibly important. If you're looking to open a shop or restaurant, you'll want to be in an area with guaranteed footfall and that isn't close to the competition. If you'll be having regular meetings with clients and suppliers, it's important to be in an area that is easily accessed by road and public transport.
Being in an undesirable area could make it difficult to hire employees - if your business is in London for example, you're far more likely to attract talented people if you're based in Zone 1 rather than Zone 6. On the flip side, the more central your location, the more you'll probably have to pay, but don't be afraid to negotiate on price!