Attention to the unique keyboard commands
Do not overuse the Spacebar. It should only be used for its purpose : separating two words. If you want to space your content in the page, use the align buttons found in the visual editor.
If you wish to go to the next line without skipping a line, do not use the Enter key. If you wish to go to the next line without changing paragraphs hit Shift + Enter. When you use the Enter key, the visual editor understands that you want to end the current paragraph and start a new paragraph.