One guideline common to many physical activity guidelines around the world is to do muscle strengthening exercises at least 2 days per week. For the purposes of posture improvement and maintenance, there are (at least) two ways to incorporate strength sessions in your routine, depending on how long you’ve been doing corrective exercises (HABIT#1).
For beginners, you can add a weekly training session (at home or at the gym) to supplement your daily corrective regimen. This session can include beginner strength exercises such as: bench rows, inverted rows, planks, Palloff press, goblet squat.
After you’ve been doing your daily corrective exercises for several weeks or months, you can gradually replace them with more advanced strength exercises performed 1, 2, or 3 times per week. This will help maintain any posture improvement you have attained without having to perform corrective exercises every day (which would not be very time-efficient). This sessions can include more advanced exercises such as: weighted squats, deadlift, pullups, etc.