What are some methods to align switches in a multi-gang box?
Vertical alignment is rarely an issue if you've installed your box level. There's not much play in the mounting holes of the devices. You can usually work a row of switches into a plate without a problem, for example.
To get them horizontally aligned:

Always start by centering the mounting screws in their slots.
Make adjustments if necessary.

Optionally leave the mounting screws just loose enough that you can slip the devices sideways as needed to fit the plate.