In order to live a secure online life, we recommend doing these steps for general online security.
1. Avoid public Wi-Fi in general, but especially when using FTP, email, etc. unless you're connecting securely via SFTP, or POP3 / IMAP via SSL or another secure method. Even then, there are man in the middle attacks. These rules apply to laptops, cellphones, tablets, and any other device that can access networks. Note: The same security concerns apply while using home Wi-Fi networks as well, and we often recommend disabling Wi-Fi at home and using wired internet consistently.
2. Avoid using "other" computers in public places, and even those from friends, relatives, etc. Phones, tablets, and other devices also fall under this same warning. Never assume that your friends, family & relatives don't already have virii / trojans / etc. on their system.
3. Reset your passwords often, but especially after accessing any Wi-Fi networks or logging in from other systems.
4. Don't share account login details. If you have to share them for any reason, always change your passwords afterwards.
5. Don't share passwords with 3rd party sites, or use the same password on other sites. We recommend the free application KeePassX for keeping hordes of passwords manageable and storing the password database on an encrypted drive.
6. Keep software up to date, whether locally (your computers, tablets, phones) or on your hosting account. Remove unnecessary software that could potentially be exploited -- e.g. use as few plugins as feasible for scripts like WordPress, Joomla, Drupal and other content management systems. The same applies to your home computer -- remove unused software, or software that is commonly exploited like Adobe Flash, Adobe PDF applications, etc.
8. Most of all, keep backups. Bad things happen and you'll want to ensure you've got a copy of your data to restore.