I want to highlight all the emails that came from a particular friend. How can I do that in Gmail?
Just use labels and a filter.
- At the top of your inbox click labels.
- Click Manage Labels.
- Click Create New Label.
- Enter a name, let's say "Emails from my friend."
- At the top of the screen to the right of the search click Create a filter.
- In the from field enter your friend's email address, e.g. firstname.lastname@example.org
- Click Next Step.
- Tick Apply the label: and choose "Emails from my friend" or whatever you named your label.
- Tick Apply filter to x conversations below then click Create filter.
You will now have a label on the left hand side of your inbox. Clicking this will show all emails from your friend. It will also add the label to all the emails from your friend in whatever folder they are currently in (e.g. your inbox).
Have a look at changing the colour of the label to make it stand out. As an example this is what two of mine look like: