I use Duolingo as well but read Spanish newspapers, when you go to a Latin American restaurant read the Spanish menus, watch Spanish TV, listen to the radio in Spanish. Try not to speak English and get friends from Latin American countries. I had a girl from Uruguay stay with me for 2 weeks. I learned a lot from her, I also used to live with a Puerto Rican family. Believe it or not I still can’t speak full conversations.