Keep headers/logos under 125 pixels high. It takes up valuable viewing space, especially for laptop users, that is best left for the good stuff to appear"above the fold" Take a cue from the big companies, simple logos done well say it all. This is our #1 pet peeve - screaming logos and headers!
I back up my blogs using a free plugin WP DB Backup. I can always restore my blog to the 13, if anything happens. I use WP Security Scan plugin that is free to scan my site regularly and requests that are suspicious-looking to be blocked by WordPress Firewall to how to fix hacked wordpress site.
No software system is resistant to vulnerabilities and bugs. Security holes will be discovered and men will do their best to exploit them. Keeping your software up-to-date is a fantastic way once security holes are found, because their products will be fixed by software sellers.
Keep control of your assets that are online - Nothing is worse than getting your livelihood in the hands of somebody else. Why take chances with something as important as your website?
Can you see that folder Imagine if you go to WP-Content/plugins? If so, upload this blank Index.html file inside that folder as well so people can not view what plugins you have. Someone can use that to get access because even if your existing version of WordPress is current, if you are useful reference using a plugin or an old plugin with a security hole.
Change your password, or at least your WordPress password and admin username and collect and utilize other WordPress safety tips to keep hackers out!