To get started, it typically helps to have some sort of motivation, whether it's to look better, feel better, improve health, prevent diseases, etc.
But the important thing is that this motivation has a basis on which you can develop a fitness lifestyle.
What I mean is that to be able to reach a certain level, you have to turn exercise into a habit and lifestyle, not a chore to be done.
If you enjoy your job, you'd love to go to work.
If you hate your job, you still have to go to work for the money, but you'll despise every moment of it.
Though not in that extreme I believe exercise is the same way. Although not all people have the intrinsic affinity towards exercise, I believe just THINKING about exercise in a positive light puts you in a favorable position to adhere to your workouts.
Anyway, as for actually getting started, it's always good to develop a solid base.
The Holy Trinity (push ups, pull ups, sit ups) is pretty much the foundation of upper body exercise. Therefore, it's only natural that you get these skills way up, otherwise you'll collapse if you try to move to harder exercises prematurely.
Would you take a Calculus class when you don't even know Algebra? Hopefully not, otherwise you're setting yourself up for disappointment.
So, if you don't know where to start, you should try to gauge your level based on the maximum repetitions you can perform from the Holy Trinity.
Here's a (very biased and subjective) standard I figure represents the population:
0-10 = beginner.
11-20 = intermediate.
21-30 = higher intermediate
31-40 = advanced
41+ = good to go!
0-3 = beginner.
4-7 = intermediate.
8-13 = higher intermediate.
14-20 = advanced
21+ = good to go!
Sit Ups (note: these are sit ups, not crunches):
0-10 = beginner.
11-25 = intermediate.
26-40 = higher intermediate.
41-60 = advanced
61+ = good to go!
Assuming you're coming off a "never really exercised" basis with no weightlifting background, these exercises will be great in every way.
Definite strength gains, eventual visible results, and hopefully confidence in your ability to be able to move your body in a decisive and controlled manner.
So before you start thinking about impressive looking gymnastic skills and all that stuff it'd be a good idea to develop a solid base.
Not to say you should stop doing the skill progressions, just keep in mind to SUPPLEMENT them with these basic exercises to build the strength necessary to do them.
I think higher intermediate is where you want to be before you start doing crazy stuff like levers and certain multi-plane movements.