Things you can do Right Now to ensure better security on your Mac.
1 .Turn off login items in Users and Groups System Preferences - Login items are pieces of software that launch every time you turn on your computer. Sometimes expired or corrupt pieces of software are listed here, slowing down or exposing your computer.
2. Turn off Filevault in Security System Preferences - Filevault is an extra layer of security that most of us don't need on our machines, and can slow your machine down, and potential render it irretrievable if you lose or forget your password.
3. Turn on Firewall in Security System Preferences - Your firewall will help keep unwanted connections away from your machine.
4. Check Extensions in Safari Preferences - Some types of malware will install extensions into Safari, like search preferences and corrupt toolbars. Remove anything you don't remember installing.
5. Clear Cookies in Safari Preferences - Some say daily, some say less often, but you should delete your cookies periodically.
6. Do a malware scan with Malwarebytes free software - Malwarebytes is the only software I use to clear malware from clients' computers
7. Check that there are no proxy options in your Network settings - This is a recent one I've seen that can affect internet connectivity.
8. Create better passwords and record them somewhere handy - Some people like password managers like OnePassword and Last Pass. I say paper and pen are also a technology, and there's less of a learning curve.
9. Create a redundant Time Machine backup and store it in a fire-safe box - Your data is the only thing that matters on your computer, 1 TB hard drives can be as cheap as $75. each, data retrieval starts at $1000.
10. Change your default browser to Firefox and search engine to Duck Duck Go - If your privacy means anything to you, try using more privacy oriented resources.