Tips of potter's tools left inside (5)
I believe the answer is:
clues
'tips' is the definition.
'potter's tools left inside' is the wordplay.
'potter's' becomes 'cue's' (a cue pots balls in snooker etc).
'tools left' becomes 'l' (I am not sure about this - if you are sure you should believe this answer much more).
'inside' indicates putting letters inside.
'cues' going around 'l' is 'CLUES'.
'of' is the link.
Can you help me to learn more?
(Other definitions for clues that I've seen before include "Hints (that you're looking at?)" , "Crossword aids" , "Here, they're across and down" , "Indications" .)