What is the best width and height of an html background to keep it from 'tiling'?

i tried to place a background i made on adobe photoshop cs2 and it keeps on tiling and i want it to be centered. how can i make it so? also when i place images, they go to the border of my background, how can i keep it off the border of my background image? how can i also make images and text side by side? if you can please provide a code that will work on notepad(i'm making it from scratch because it's a project of mine to be submitted tomorrow in school)