How to prevent side scroll

A very common mistake that I have noticed is people using the space bar to expand their page. This means that the page will only display correctly for visitors who have the same screen resolution as the page designer.
To create pages that will look good on all screen resolutions (800x600 pixels and above) you should go to Use HTML to create your page (at the bottom of the page editor) and set the table width to 100% by adding the code in red as shown below:

<TABLE borderColor=#000000 cellSpacing=1 cellPadding=1 width="100%" 

If you want to center text or graphics on your page, once again don't use the space bar to do so, use the Center Justify icon on the toolbar instead:

Also you should not use any graphics wider than 600 pixels. To check the size of the picture you want to use, right click it, select properties and look at the dimensions.

Another thing to avoid is putting large graphics next to each other; if the combined width comes to more than 600 pixels.