My words will not be as effective as my sensei, Mark Crilley
I myself have been studying the art of making comics for seven years. Here are some tips
1) to make your pages more effective is to be a good storyteller. Don't let pages numbers stress you out. Use as many or as little as pages and panels as you need to make sure the sequences are consistent and the pace is how you want it.
2) composition. If you feel like your scene is stale, try telling your story from a different angle, point of view, close ups, etc..
When you watch a movie, how many different camera angles do you see in just one scene? Think about that when you draw your thumbnails. Composition is important for every aspect of visual art.
3) speech bubbles and sound effects.
Use this effectively. Make sure your speech bubbles are in the order, and are easy to follow. Sound Effects are a huge part of the graphic novel anatomy. It can be small or large and cover a lot of the panel.
4) Backgrounds
They have to stay consistent throughout the scene. It helps the readers feel the atmosphere and know where your characters are.
5) Movement
Characters and objects should never be drawn like stillwater. Even if they're standing in line at a grocery store...
Stan Lee's book about comics can explain this much better than me. I advise you to look it up.
Those are some of my tips. I hope I helped you out a bit.