Think Forward, Look Backward
Beethoven based his early works on the models of Haydn, then broke away and formed his own rules and interpretation. Brahms did the same with Beethoven. Stravinsky rewrote Pergolesi and discovered Neo-Classicism. Schoenberg looked to expand the harmonic language of Wagner and developed his Twelve-Tone Method.
Look at other composer’s ideas, take what speaks to you and leave the rest. Make them completely your own, reinvent them in your own idiom. The reinvention develops your idiom.
Think Forward, look Backward