If there are certain Dashboards you work with all the time, there are a few ways you can set them to quick access. Two ways are described in this tutorial: Setting a Dashboard as personal preference, and setting a Dashboard as default.
A 'personal preference' Dashboard will be the first Dashboard to open whenever you go to 'Home' in the left side navigation menu.
A 'default' Dashboard will be the first Dashboard to open whenever you open ANY Dashboard view. Of course, you can still navigate to all the other Dashboards via the view drop-down.
This tutorial shows you how to do both, so you can streamline your work effectiveness by always having quick access to your favorite Dashboards.