Sounds like you are not using a domain.
In which case, you won't have common objects between the two machines like you would on a windows domain.
In the past using Workgroups, I would set up identical user accounts (same username, same password) on both/all machines. Windows, when connecting to a remote machine, will attempt to authenticate with it's current credentials. Having matching credentials on the remote machine means it just 'works' under normal conditions.
However, with Windows 7 there is "Home Groups" which can somewhat simplify the sharing of files and printers between computers. If all your machines are windows 7 or up, look in to using home groups to share resources around your network.
If you have a mixture of devices, you might be better off simply buying a cheap NAS box and pointing all your machines to that instead, or perhaps your router has a USB port that can share an external USB hard drive for you without the cost of buying a dedicated NAS.