I've worked on comics a long time. Here's some tips:

Never design anything you're not willing to draw a hundred more times.

Word balloon placement is more important than drawing skills.

Not every panel needs a background.

Characters speaking in a panel mouths should be open.When you sketch layout your page, include your dialog and sound fx.

People really do notice if you copy and paste your panels.

Color comics sell better.

Your panel borders should be obvious.

Do your best to place characters in a panel into the order that they are speaking.Use dynamic perspective to heighten drama of a panel. Leave it out if a panel doesn't need it.

Word balloon tails should point at the mouths of the speaker.

If you don't need dynamic panel shapes, don't use them. Prioritize being able to read the page clearly.

Clarity is key.If you flip your canvas a lot, mark which arms are right and left.

People appreciate their favorite character in a crowd shot, preferably doing something unique to them. But don't overload on crowd shots. Every crowd or group scene increases your workload a hundred times over.

Also getting words to fit neatly in a speech balloon with just the right amount of space around the words is a subtle magic.

Also words on a comic page always seem to take up like, 5 times more space than I think they will.