Complex sentence: Dorsey advised Sinatra to listen to Bing Crosby, the only singer Dorsey thought that Sinatra should emulate, and as his success and popularity grew, Sinatra pushed Dorsey to allow him to record some solo songs.
Split into simpler sentences: Dorsey advised Sinatra to listen to Bing Crosby, the only singer Dorsey thought that Sinatra should emulate. As his success and popularity grew, Sinatra pushed Dorsey to allow Sinatra to record some solo songs.