Questions about selectors

Been using Uipath Studio for a while and it is a great tool. The only problem is that when I do an element click on a web page, I often inexplicably have trouble finding the element. Yesterday it was working fine, today it might be a problem. I think there is something wrong with my selector, please can you recommend any tutorials on this, about all aspects of the selector, thanks!

Hey!

Open the selectors with UiExplorer and share us the Selector screenshot?

Regards,
NaNi