How can I make high-quality banner images for my coding tutorials?

Hi everyone! I'm working on creating high-quality banner images for my coding tutorials and would love some guidance on best practices in Photoshop. I want the banners to be visually engaging while maintaining a professional look. Are there specific resolution, color settings, or design tips that will help my images stand out without compromising quality on different devices? I'm also looking for honest feedback on the current banners I’m using on my website (Checkout ) what can I improve to make them more appealing and effective for visitors? Thank you in advance for your advice and suggestions!