Styes are unpleasant to look at (8)
I believe the answer is:
eyesores
'styes' is the definition.
(I've seen this in another clue)
'unpleasant to look at' is the wordplay.
'unpleasant' becomes 'sores' (I am not sure about this - if you are sure you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'look at' becomes 'eye' (I've seen this in another clue).
'sores' after 'eye' is 'EYESORES'.
'are' is the link.
Can you help me to learn more?
(Other definitions for eyesores that I've seen before include "views people find offensive" , "They are offensive to see" , "Very ugly and offensive sights" , "unattractive prospects" , "Things that are ugly to look at, hurt optics" .)