The title and your name will be seen in the first 11 seconds that a person looks at the poster because they will be centered at the top. This will be all many people will read, so the poster title should be your punch line. The overall format of a good poster is dictated by the way we assimilate information. For example, you would never put your first panel on the right and ask your reader to proceed to the left because we are not trained to read that way. A left to right horizontal rows arrangement works too but is not as common, probably because it would require a reader to walk back and forth in front of the poster, which could be difficult in a crowded session.
Books leave space on the margins and by having chapters.
Posters that are crammed with information are tiring to read and are seldom read in their entirety. Omit all extraneous text or visual distractions, including borders between related data and text, so the reader can assimilate your ideas easily. Size of poster elements or the fonts in each element can serve to emphasize the main points. For example, making your subheadings in all capitals and significantly larger than the rest of the text on the same panel will draw the reader's eye first, and so be emphasized. You will lend the most power to your words if you spatially arrange the text in each panel of your poster following the same principles used for the poster layout as a whole.