Rank thirtieth among wedding celebrations, not first (4)
I believe the answer is:
earl
'rank thirtieth' is the definition.
'earl' can be an answer for 'rank' (I've seen this before). I am not certain of the 'thirtieth' bit.
'among wedding celebrations not first' is the wordplay.
'among' indicates putting letters inside (I've seen this in other clues).
'wedding celebrations not' becomes 'erl' (I can't justify this - if you can you should believe this answer much more).
'first' becomes 'a'.
'erl' enclosing 'a' is 'EARL'.
Can you help me to learn more?
(Other definitions for earl that I've seen before include "Aristocrat ranking between marquis and viscount" , "Rank immediately above viscount" , "A real peer" , "House member" , "One who's been elevated" .)