Install the clean hacked wordpress site Firewall Plugin. This plugin investigates requests with heuristics that are simple to recognize and stop most obvious attacks.
Strong passwords - Do what you can to use a password, alpha-numeric. Easy to remember passwords are easy to guess!
Keeping your WordPress site up-to-date is one of the most easy things you can do. For the past couple of versions, the ability to set up updates has been included by WordPress. Not only that, but sites are notified whenever a new update becomes available.
WordPress is one of the most popular platforms for sites and self-hosted blogs. While WordPress is pretty secure from the box, there are always going to be people who want to make trouble more by finding a way to split into accounts or sites to cause damage or inject hidden spammy links. That is why it's essential to make certain that your WordPress installation is as safe as possible.
Do your homework and some hunting, but if you are pressed for time and want to get this done once and for all, try the WordPress safety plugin that I use. It is a relief to know that my website (and company!) are secure.