DISCLAIMER: Do not continue to do any exercises if you feel pain, dizziness, or if your condition becomes worse. Please report any issues to your chiropractor medical doctor before continuing.
Maintaining long-term better posture will require some work and effort doing exercises. Start with the neck and mid back exercises if you work on a computer all day. Start with the neck even if you don't work on a computer, because chances are you've never exercises your neck before!
Just remember to take it easy and stop if feel any pain or dizziness! If you find the exercise seems to be working the same area and you like one more than another, just stick with the one you like. The key is to be consistent!