It helps rider excite royal interest (7)
I believe the answer is:
stirrup
'it helps rider' is the definition.
The definition suggests a singular noun which matches the answer.
'excite royal interest' is the wordplay.
'excite' becomes 'stir' (synonyms).
'royal' becomes 'r' (abbreviation).
'interest' becomes 'up' (I can't justify this - if you can you should give a lot more credence to this answer).
'stir'+'r'+'up'='STIRRUP'
Can you help me to learn more?
(Other definitions for stirrup that I've seen before include "Rider's foot rest" , "Equine foot rest" , "Small bone of the middle ear - it purrs (anag)" , "Rider's foot loop" , "In which a rider's foot rests" .)