Firstly, have you checked to see if W7 drivers are available for your laptop and printers etc.? If not, I suggest you desist. You might get a printer working with a Vista driver (check the Internet to see if anyone else has), but unless you have drivers for the actual laptop itself you are unlikely IMHO to get a stable system out of it.
If they are available there is a lot of information from Microsoft about how to do it. You can do an in-pace upgrade:
Upgrading from Windows Vista to Windows 7 - Help & How-to - Microsoft Windows
Or a custom installation upgrade:
Upgrading from Windows Vista to Windows 7 (custom installation) - Help & How-to - Microsoft Windows
Personally I would never go the upgrade route - so many windows installations have been doomed from the outset as they are the result of upgrading a system that (possibly unbeknown to the user) had problems with the registry.