The first thing to do is to develop a strategy (i.e. be organised!) for saving data into your computer, whether from emails or anywhere else.
This means creating folders that correspond to what it is you are saving. You might receive emails related to family photos, circulars from the gardening club, minutes from church meetings, posters related to various community matters and nice emails from your husband etc etc.
Some of these folders will need to have sub folders - e.g. posters will arrive from school and church. To make it easy to save and also to find later, school can be made a sub folder of posters, as can church.
You should develop a folder strategy on paper before continuing.