While we normally prefer the CLI (or CloudFormation) for creating AWS resources the wizard for creating alarms does a lot of work for you, so it is a good place to start. Once you know what kinds of alarms you are interested in, you can automate them.
The CloudWatch console is a great place to keep an eye on the performance of your resources. Often when looking at the metrics you might find a scenario that you would want to be notified of, and quickly create an alarm on it.
While e-mail is probably the easiest way to get started with alarms, it doesn't scale all that well (Do you really want more e-mail?). For very important metrics you might want a CloudWatch dashboard instead, or a different notification protocol/target. ...
