You and me succeeding a right pair is difficult (7)
I believe the answer is:
arduous
'difficult' is the definition.
(thesaurus)
'you and me succeeding a right pair' is the wordplay.
'you and me' becomes 'us'.
'succeeding' means one lot of letters go next to another (succeeding can mean going after or following).
'a right' becomes 'ar' (I've seen this in other clues**).
'pair' becomes 'duo' ('duo' can be a synonym of 'pair').
'ar'+'duo'='arduo'
'us' after 'arduo' is 'ARDUOUS'.
'is' is the link.
(Other definitions for arduous that I've seen before include "Requiring hard work" , "Gruelling, strenuous" , "Fatiguing (task)" , "Backbreaking" , "Burdensome" .)