Trailhead has a nice overview of Page Layouts https://developer.salesforce.com/trailhead/force_com_introduction/customizing_user_interface/ui_page_layouts
Page Layout Notes
- If the user's profile does not have access to ALL fields in a section via Field-Level Security, then that section heading will not be shown. Nice to know.
- If the user's profile does not have access to a lookup field to this object on one of the related objects, the related list will STILL be shown on this object. This is not good. This is why you need different page layouts per Profile.
Different Layout Types
Compact Layouts are for the Salesforce Mobile App. Mini Layouts are for Hover links and the Console.
Custom Buttons and Links
Trailhead has a nice overview https://developer.salesforce.com/trailhead/force_com_introduction/customizing_user_interface/ui_nav_buttons_links
The Stack Exchange questions at Make a button on a layout be visible only to a specific group of users have some great suggestions for buttons and links too.