Things Cassandra has learned by trial and error so far, since I’ve never taken courses or anything. This should make all you graphic design students laugh your asses off:
1. Start in CMYK, not RGB. When you start in RGB it will take you five or six hours to rebuild what you made in CMYK and it will not look the same because Photoshop doesn’t handle transparency and layer effects the same way between color types.You can -always- save copies of (and you should), and mode-convert to RGB and Save For Web.
2. Start your graphic way bigger than it needs to be for the final intended print size. By several orders of magnitude. You can always downsize and dumb it down once you’re done. If you’re designing a postcard, make sure to make it at at least 8×14 poster size, if not larger. If you get an unexpected response to a design and you can’t upsize it to meet demand, you are hurting your own bottom line.
3. Flatten your layers with care. Do it wrong and it’ll screw up your effects. And always, always save your original with the layers seperated. You’ll kick yourself if you want to make a change later and you can’t because the master PSD is flattened.
4. Remember to include at least 1/4 bleed on all sides and 1/8 for text from the edges -inside- the bleed. Templates are your friends. If your printer gives you one for your intended print size, definitely use it.
5. Find out what color profile your printer uses and set your original print file to that. Don’t use SWOP settings if your printer is not doing that. Don’t use matte if your printer does everything gloss. A quick phone call to your chosen printer should resolve most of these issues.
6. If you really care about your black and white quality, go to a printer, not a photocopier. I took a zine project to Kinkos for copying but regretted it- an 8×11 that was primarily black came out almost unreadable because of the way the photocopier laid down the toner. There were nasty areas and I just didn’t like the overall look. If your design is mostly whitespace it’s probably fine to run it through a copier, but if you really need depthful black, don’t bother photocopying.
7. There are different profiles of CMYK between printers. Prepare to tear your hair out over this one. Even though it’s standard, supposedly, it’s really not, because ink mixes, papers, and even the machines themselves produce slight to dramatic variations. Also be prepared to cry that after you’ve spent a lot of time figuring out your Pantone color palette, the printer will then tell you to ditch them.
8. Kinko’s converts everything color to RGB for their machines. This was a surprise to me; hopefully not to you, now.
9. Always start in 300 dpi minimum. (thanks Nijhazer!) 72 dpi is web-standard, but what you’ll find is that it’s absolute fail when it comes to pro-level printing. I actually like starting in 480 dpi, but some printers will cap off at 300; this is another case where Asking Your Printer ahead of time will save you hours of grief later. Most of the time they’ll specify a lot of information right on their website, but it’s good to call if you have questions. That’s their job, to help you, their client. Don’t be afraid to pick up the phone.