Think Backwards
Every process has its constraints. For example, jpegs taken from a website, typically RGB, 72 dpi, will not work if used in a brochure sent to a high resolution imagesetter for offset printing, needing CMYK and 300 dpi. So before you start the project, think of the end result and the requirements for that process. If you are in doubt, ask. We are more than happy to give you the information you need for successful output. Here's a tip. If you're not sure, or if your project is going to be used for both the web and a brochure, start high. Everything can always be made lower in resolution (downsampled) for repurposing. This is not possible going the other direction. Once the information in the file (resolution) is gone, it's gone. There is no way to put it back for acceptable results. Make sure the project you're creating meets the requirements for the chosen output.
Fonts
Nothing can bring a print job to a screeching halt faster than missing or corrupt fonts. One of the best things you can do for your desktop publishing is to organize, update, and repair your fonts. A font utility like FontDoctor, available for both Mac and Windows, can be a great help. It will search your hard drive for fonts, allow you to update them so newer applications can use them properly, and give you the option to move or copy them into an organized font library. Apple has a short tutorial about font management built into OS X or check out the PDF Fonts in OS X. Extensis has a great publication called Best Practices for Managing Fonts in OS X
If you choose to move your fonts, remember that the Operating System, OS 9, OS X and Windows need to have certain fonts left in the font folder in the System folder for the Operating System to work correctly.
For OS 9 these fonts are located in System Folder/Fonts. Don't move Charcoal, Chicago, Geneva or Monaco.
For OS X (10.3.x) they are located in System/Library/Fonts. Don't move Arial, Arial black, Courier.dfont, Geneva.dfont, Helvetica.dfont, Keyboard.font, LastResort.dfont, LucidaGrande.dfont, Monaco.dfont, Tahoma, Trebuchet MS, Verdana or Webdings. Be aware that OS X has a couple other font folders: Library/Fonts and Users/Library/Fonts as well. The fonts in these folders can and should be removed if you are using third-party font management utility or want to have complete contol of your fonts.
If you want to activate fonts in OS X without using a font management utility, drag them into the Library/Fonts folder. If you have them organized into folders by client or project, there is no need to take them out of their folders, OS X will recognize them inside the folders. To deactivate the fonts, drag the folder out of the Library/Fonts folder. As an added bonus, OS X will also use PC fonts. To use fonts from a PC, drag them into the same Library/Fonts folder.
For Windows XP see Adobe's publication, TrueType fonts installed by Windows XP. Window's fonts are located in the Windows/Fonts folder.
If you take the time to take care of your fonts, you can be assured that your job will not be held up by corrupt or missing fonts and will print correctly.
When you send your job to us, make sure you include all the fonts used in the document. For postscript fonts, please remember to send both parts. For example, if you used Times Italic in your document, be sure to send the Times Italic printer font as well.
Here's a tip. When you specify a font in a document, use the actual font from the Font Menu, ie choose Times Italic. Don't use the Style Palette in the application. It is possible to style a font, and it looks correct on the screen, but really you don't even have the font. The Style Palette makes it look correct but it may not be correct.
You can use Photoshop to layout your project but, there is a special note about Photoshop and fonts. If you are using Photoshop 7, be sure you have the 7.0.1 update. This corrects an obscur problem where Photoshop will rasterize font layers. When the document prints, the fonts will not be sharp and clean. Also, don't use the Style Palette in Photoshop to style a font to make it bold, italic, etc. Use the actual font. If you use the style palette, Photoshop will rasterize the font. When it prints, the actual font won't be used but rather a rasterized image of the font and it won't be sharp and clean.
Ink
When you send your job off to be printed make sure that if the job is to be printed as CMYK that all the colors you used in the document are CMYK and not specified as spot.
If you have a Spot color job, use that same color library in all the applications you use to create the document. For example, some applications look at PMS 185 C and PMS 185 CV as two different colors. Quark is notorious for this. Select the same color library in each application.
Better yet, a technique that is fool proof, is to use magenta for the second color. This alleviates a multitude of possible problems. The screen angles are great for duotones from Photoshop. You don't need to worry about getting spot color from Photoshop. The color names are the same across all the applications you have used. You are guaranteed that it will separate correctly. Plus it is obvious if you forgot to change the PMS color in a linked file. We have had "two-color" jobs that have had three or more PMS colors in various linked graphics. They were all green but had different PMS numbers. Evidently the designer was experimenting with greens and forgot to go back and change all the linked graphics. Even your PDF will be correct and you won't have to worry about something happening where your Spot Pantone color is inadvertently converted to CMYK.
If you need to show your client a proof, create the job with the proper PMS color then convert it to magenta before you send it to us. Be sure to let us know what PMS color the magenta represents so the correct ink will be used when it is printed.
Graphic elements
Resolution. Resolution. Resolution. As a general rule, make sure all the photos in your document are 300 dpi. Otherwise they won't work. There is no way to get around it. Various processes use different resolutions, but if you always use 300 dpi you are always safe. This is also true for grayscale images.
Also make sure they are CMYK if they are going to be printed as CMYK.
For line art the optimum is 1200 dpi but you can also use 900 dpi and can go as low as 600 dpi.