Most useful skills?

Hey, I'm an aspiring GameDev and I am using Unity currently to practice and learn. I wanted to know what the consensus for the most difficult aspect of Game Development was.

I'm currently working on my own and wanted to know what would prove to be challenging for me (Animation? Programming?), and what aspects can easily be solved.

I have decent programming knowledge though in-depth or advanced programming is beyond me. I've heard that Playmaker can help with this? I've also discovered to Morph 3D Character System which greatly improves my ability to create original 3D characters.

My goal is to make the GameDev process as easy on me as it can be so I can produce marketable original 2D and 3D games. As I cannot currently afford to hire help.

Hoping to get a better understanding of the process and industry, and what difficulties are involved that I should look out for, and perhaps how an aspiring solo dev like me can solve them.