Here is a basic guide on resolutions to use on certain applications. Can differ depending on what you are trying to achieve, paper and equipment used.
|Web||72 dpi, 96 dpi||Monitors, LCD displays|
|150 dpi||Newspapers, Low to Medium Quality Print|
|High Quality Print||300 dpi and above||Magazines, Full Colour Flyers, Banners, Business Cards, High Quality Print|