One of the most important factors in creating a manga is the use of panels. Panels allows you to control what the readers see and help emphasize moods such as endless space with a non-frame (i.e. borderless panel) or change of pace such as a flashback.
The whole page itself can be considered a panel in its own right. You will see the use of two pages as one huge panel called a "one-in-two pictures" mostly in shoujo manga where pacing is generally slower. Also, you may encounter panels of all types from regular, thin, long, short, small, and irregular shapes as shown below.
Be careful not to go too crazy with shaped paneling. There
always has to be structure behind your panels to ensure
good pacing, transition, and flow of storytelling. I'll
discuss more about pacing or timing and transitions at another
A neat feature of comics is the ability to darken the spaces around panels for a darker tone. Notice the difference between the light and the darkened spaced pages below.
As mentioned earlier, there are artists who prefer to use borderless
panels or non-frames. Each image flows from one to another
creating a muralistic effect in whole.
Other than that, another technique is the panel within the panel as shown in the example below. The entire scene is taken in from the side view moving to the girl in the background and a close-up panel of the girl. The door frame could be taken in as another panel, seperating the girl from the two in the forefront. Speaking of which, if you have the ability to use the surrounding as a "panel border", don't be afraid to do so! Other examples would be a cave entrance, trees, and even windows. You could even tilt the panel to create a sense of irregularity or movement.
As I have suggested before, to get ideas and understand paneling, it would be best if you picked up a variety of mangas for scrutinization and study. Each artist has their own techniques and observing how they panel their stories is a lesson of it's own.