"My content has good words, but it just looks amateur next to real brands."
A gap that is easier to close than you think
Looking professional is mostly about being cohesive, not fancy. When I made content for my client, I followed their branding guidelines. I used the colors of their logo, and I did not go crazy with other colors. That restraint is what made it look professional. If you understand what makes a professional, cohesive look, you can make beginner content look like it came from a real brand.
The wrong question vs the right question
Wrong question: "How do I make this look fancy and impressive?"
Better question: "How do I make this look like it clearly belongs to this brand?"
Fancy is not the goal, and chasing it often looks worse. Cohesive is the goal. Content that obviously belongs together, and to the brand, reads as professional every time.
Why I used only their colors
When I checked my client's website, I found their logo. I used the colors of that logo in my content, and I did not add a bunch of other colors on top. That single choice, sticking to their palette, made my work look cohesive and professional. It told the client, at a glance, that I understood how to create a consistent look for their brand. I did not need fancy design skills. I needed discipline and an eye for what belongs together.
The rule that came out of this
Match the brand, and remove what does not fit. Professional content is cohesive content. Use their colors, keep it consistent, and resist the urge to add more. Restraint is the skill.