What does it take to succeed in this dive?
Like any dive you wish to pursue, to succeed with acting, you will need to spend a lot of time studying, and practicing. These are the two repeated actions that will help you to master your journey towards becoming a good actor.
For those who really wish to master this skill, you should make the commitment to make the pursuit of acting a lifelong hobby.
You will have to find good study materials, good teachers, and good practice partners. Most importantly, you will have to find the discipline to study and practice and improve regularly. If you don't practice regularly, you won't make much progress, or worse, you'll make lots of progress and then forget what you've learned!
The secret to success (since we know you want to know) is quite simple: continue reading plays and screenplays, continue learning, continue practicing, master the art of listening, and constantly improve your current skill level and current techniques. The issue is that most people don't actually do any of these tasks well.
You see, most people only focus on one or two of these skills, or they focus on all six, but at a very cursory level. If you wish to master acting, however, you need to focus on all six, all the time, and spend enough time with each so that you see regular progress.
Bottom line, if you want to improve, never stop pushing for improvement.