See also: Remove spyware & adware
Use at least 8 characters. Don't use words from in any language. Instead, use a mix of lower and upper case letters, numbers and symbols.
Do not store this password where anyone can get to it.
Be aware of individuals attempting to manipulate you into divulging your password (AKA Social Engineering).
If you suspect that your password has been comprimised, change it just to be safe.
Change you computer account to general user. Most common attacks are perpetrated using the Administrator account or users having administrative privileges. If you have only basic computing privileges, attackers can’t do much. When the need arises to do administrative work, logon to that account, do the work and log off.