If Gmail stars aren't quite doing it for you, or the priority Inbox is not your thing, try this tip to quickly label or flag emails that need attention.
Gmail labels are very powerful and very customisable little things, a label can be called anything and be (nearly) any colour. Set up your own system of flags and reminders using this tip to quickly label an email.
The easiest way to label an email is to click the label name from the left-hand menu and drag and drop it onto the email. This way the emails can remain in the inbox but clearly labelled, or flagged, so that you don't miss them. Simply add a useful name - such as "Urgent" and make sure you give the label a bright, bold colour, so it stands out clearly flagging the urgent emails. This is great for the emails that need extra attention as not only does it label the email, it also stays in your inbox until it’s ready for archiving.
As a starting point for new Gmail users, when you first get your Gmail account you'll notice there are some default labels created to get you going, notably Follow up and Priority. Rather than use these labels with the archive choice to move them out of your Inbox why not use them to flag emails that may require some action from you.
If you subsequently want to get rid of a label, open the email and click on the cross next to the label at the top of the email - easy!
To keep these new "flags" where you can find them, consider nesting them under a top level Flags label - useful if you have a lot of visible labels in your left hand menu.