"Aagh! My fonts are all blurry and ugly! What do I do?"
In order to fix this issue, its important to know the basics of how GameMaker: Studio 1.4 handles fonts.
In most cases, fonts are stored in a vecotor format. What this means is that upon upscaling the font, no quality is lost. GameMaker, however, will rastorize fonts to be expored in the game package.
Example texture file containing included font
This results in a loss of quiality when the font is later upscaled when it is drawn in GameMaker. For this reason, it is important that you properly set the size of the font you intend to use in the GameMaker font menu. If you need to, include multiple sizes of the same font.
When GameMaker draws text onto the screen, it is essentially drawing a bunch of images (one for each letter or character). These characters are being "cut out" from the included texture file.
GameMaker font menu with anti-aliasing option highlighted
GameMaker has a built-in anti-aliasing feature for fonts. This helps disguise the sometimes obvious sharp edges caused by the letters being "cut out" from the texture file. However, this setting will cause blur on the edges if the font size is not set high enough.
In conclusion, you should include multiple versions of the same font for the different sizes you intend to use. You should never upscale fonts in code (when drawn), as this will cause the them to blur.