See also: Welcome to postcarding!; Designing and making postcards yourself
Nothing on this list is necessary for postcarding; the list on the newcomers page tells you what you absolutely need. But these tools can make postcarding easier, more efficient, and more effective.
Recipient Checklist is a tool that runs in your browser that can help you keep track of the addresses you're writing to. If you're writing to addresses supplied by Activate America or Postcards to Voters, those organizations supply it in a format that Recipient Checklist can import.
Print this on letter-size cardstock and use a craft knife (X-Acto knife) and cutting mat to cut along the diagonal lines to make the corner slits that hold each postcard. Fill out one postcard, then put it in the upper slot; then, put each postcard after it into the lower slot and copy your script from the upper to the lower.
If you don't have letter-size cardstock, plain paper will do, or you could cut 12-by-12-inch cardstock down to letter size (or at least 8.5-inch width for printing).
Download the postcard holder as a PDF.
So, you've got a postcard design you made yourself, or one of my designs, or some other print-at-home design… but you don't have a printer, or don't feel comfortable trying to print it at home. (I do have instructions on doing that if you want to give it a try.)
Corporate print shops (including FedEx Kinko's, Staples and Office Depot, and pharmacy photo kiosks) vary in how well they'll serve this need. The most important thing is that postcards are 4 by 6 inches—there is some room for variation in the definition of a postcard, but the range is fairly narrow. A 5-by-7 card is not a postcard even if a print shop claims it is—you will need letter stamps to mail such a thing.
At a local print shop, you may need to supply the postcard back as well. I have a generic blank postcard back you can use for any 4-by-6 or 6-by-4 image.
Assuming you're supplying both the front (image) and back, here's what you'll need to tell the print shop:
The size: 4-by-6 or 6-by-4. Do not accept upsells or promotions of larger sizes such as 5-by-7.
The specific paper you want. This is best sorted out with an in-person visit where you can look at samples. You probably want “cover stock” of at least a 60- to 110-pound basis weight. You can decide for yourself whether you want uncoated, matte, semi-gloss, or gloss (you probably don't want gloss). For most designs, you probably want some flavor of white.
They may not allow you to supply paper yourself. You can ask, but you may have to choose from among the options they offer.
Whether the design is in color or black-and-white. This may or may not matter depending on the shop, but it's good to state it up front.
If any part of the front image is meant to extend off of the edge of the page (card), that is called a bleed and you must tell the print shop you want that.
This is necessary because the bleed section will be literally cut off with a paper trimmer; that's how they ensure it makes it all the way to the edge.
How many postcards you want. This will depend on how many postcards you plan on writing, whether you can enlist any friends to join you, and cost.
Give your print shop all of the information from the above bullet points (size, paper, color or B&W, bleed) and ask how much it would cost for 100, 500, and 1000 postcards. (Generally, the cost per card goes down for larger orders; as long as the design isn't anchored in time to a particular election, you can reuse any leftover cards for future postcarding.)
It is never too early to order postcards. If you wait until too late, such that you need them ASAP, you may have to pay a rush fee; otherwise, there is nothing wrong with ordering postcards as far back as January.