The most commonly used formatting options (styling, numeric/currency formats, freezing panes, etc.) are available in the formatting bar above the spreadsheet.
Conditional formatting can be especially useful when coupled with dynamic data from lookup functions to offer changing views.
You can also use the color function to add styling to a cell based on custom logic. Similarly, the tooltip function can be used to have a tooltip show custom content when the user hovers on a cell.
The decimal and thousands separators can be changed by clicking the Numeric settings button under the Document tab.