Welcome to both the world of Macs and to the forum.

1. Make sure you set up and use Time Machine
2. Get a copy of Disk Warrior and run it every couple of months to keep your file system in order
3. You can run a permissions repair via disk utility, but it's not a major thing as it only repairs permission on some items.
4. A copy of "The Missing Manual" by David Pogue is a great resource to have - he even includes a chapter on switching.