Grammatically, be able to talk about the past, present, and future. Learn the verbs and verb patterns that allow you to speak in those tenses, and focus on building real conversations with real people by forming questions and answers around those verbs. Don't study a list of verbs, then a list of prepositions, and so on. Organize what you're learning into 3 categories: past, present, and future.
Conversationally, be able to talk about the past, present, and future. Learn the words and phrases you need to talk about what really happened today, what's going on right now, and what you're doing tomorrow.
Grammatically: past, present, future
Conversationally: past, present, future