Update your WordPress installation, themes and plugins (though we do recommend testing updates on a localhost installation or on a staging site first). And if theme or plugin you’re currently using hasn’t been updated in the last couple years you might want to consider switching to a new one.
Don’t install illegal downloads of premium themes and plugins, which almost always include malicious code (virus, spam, hacker backdoor, etc).
Only use plugins and themes from trustworthy websites. We don’t recommend downloading from forums or third party sharing sites (torrents). If you aren’t sure of a website’s trustworthiness check customer reviews, item ratings and social accounts.