Besides hiding login url, you can check following for better security.
1. Make sure all plugins, themes and wordpress is updated to latest stable release.
2. Delete plugins that you do not use.
3. Remove themes that you do not use.
4. Use plugins from known and credible authors.
5. Also refer – http://www.wpbeginner.com/wp-tutorials/11-vital-tips-and-hacks-to-protect-your-wordpress-admin-area/