The starting point for keeping your information safe is knowing what the threats are.
The threats to any asset are traditionally theft, fire and flood and vandalism. To these we can add dependency on electrical power for our information as computers depend upon power to work. However, the level and type of these risks is different if we keep our information on computer.
Computers are attractive to thieves, not for their value to you as the repository of your information, but as an easily removed and disposed-of asset. This means that a burglar is much more likely to break in and steal a computer than a filing cabinet. The value to you of the information held on the computer is likely to be much more than that of the computer itself.
Computers are as vulnerable to fire and flood as any other asset, but vandalism comes in many forms, some of which are unique to computers. Computer hackers are probably not interested in you, but in the mischief that they can cause across the world. However, a computer virus inherited via an email or over the Internet could destroy your information, even its source was on the other side of the world.