When you first research a technology that reveals a new resource on the map (eg. Electricity reveals Aluminum), you can click the tip that comes up to center the map on deposits of that resource that are near your cities.
Is there a way to easily find those Strategic Resources again on later turns? So far I haven’t found any method other than hovering my mouse over all of the tiles near where I thought it was to try to locate it.
You can turn on the “resource icon” overlay which will put up floating icons showing what all the resources are (Ctrl+R, or click on the “toggle map options” button to the left of the mini-map and tick “resource icons”).
If you then zoom out you should be able to see where the resources are quite easily, and what they are.