I don't think it's a skill that you either have or you don't.
I think everyone can do it but it just depends on what level you are at.
But I would agree in saying that the "art of manifesting" requires a skill set and you can get better at it with practice.
Manifesting things itself is actually pretty easy.
It's all the problems and obstacles people have that make it confusing.
These obstacles such as limiting beliefs, low self confidence, negative attitude towards money etc. can make it more difficult to manifest.
So everyone is different.
Someone who doesn't have any of those negative obstacles will be able to manifest easily and quickly and to most it will seem effortlessly.
The reason they can do so is because they don't have any of the problems that cause manifesting to not work or at least slow down.
So what you really need to do is work out if you have any potential road blocks, if you have any of the obstacles that could make your manifesting not work and if you don't then manifesting should be a piece of cake for you!
If you do then become aware of them, fix them and then manifesting will become a piece of cake for you
Tristan