Information Security Framework, Pt I: the Basics:

Let's start with the simple things.

1. Keeping up-to-date on all things software-related on the machine should be paramount.

Not just operating system updates though.

Software updates for things like word processing programs, music players, email clients, etc.

Kernel and BIOS updates for the machine itself.

If you want to check for the newest BIOS update, look at your computer hardware, visit the vendor's site, and they will have BIOS downloads available, as well as the date they became available.

Keep in mind, some updates on the BIOS itself aren't always necessary.

If the vendor recommends "Not updating if stability isn't a problem, then don't do it"

2. Next, let's talk about things that may communicate over the local network or within a short proximity, such as Bluetooth, airdrop, etc.

If you're not using them, turn them off.

Airdrop is especially troublesome because often I'll be at an airport and see dozens of individuals who have airdrop enabled. I recommend setting it to 'Contacts only' unless you're intending to pass a file to someone close to you.