You can purchase security plugins . There are safety plugins out there that guarantees security for your own blog. One is called how to fix hacked wordpress Scan. This plugin continuously scans the system . It also updates the security so that the system can not be penetrated by new hackers.
Strong passwords - Do your best to use a password, alpha-numeric, with upper and lower case and special characters. Easy to remember passwords are easy to guess!
You also need to set the"Anyone Can Register" in official source Settings/General to off, and you should have some type of spam plugin. Akismet is the one I use, the old standby, but there are lots of them these days.
You can create a firewall that blocks hackers. The firewall prevents the hacker from coming into your files. You also have to have version of Apache. Upgrade your PHP as well. It's essential that your system is always full of upgrades.
Don't use wp_ as a prefix for your databases. Most web hosting providers are removing that default but if yours doesn't, adjust wp_ to anything other else but that.