Pinterest has become more and more popular in the last few years and is a big referrer for Instructables. Many people have found out how to utilize Pinterest to its fullest and one of those ways is to create a long pin. This takes up more space on Pinterest and gives you more of an opportunity to draw people in to click on your pin.
You can take the time to use Photoshop to make a pin, but there is an even faster and easier way to do it using Picmonkey.com. It's a free website that anyone can use. It might take you a pin or two to get the hang of it, but it gets really easy the more you do it.
Before you can make your pin, you need photos.
While photographing your Instructable, keep Pinterest in mind. In my opinion, there are 3 main formats to focus on when you go to make a long pin and you'll need to think about what you are going to do even while taking pictures of your project.
Long Pin Formats
The reason you need to think about this while making your project is different for each type of pin.
For #1, you are probably going to want to make sure you have an image that is longer vertically, so it won't be so small on Pinterest (horizontal images show up small on Pinterest). Also, if you are going to add a text overlay, you probably want to plan that when setting up your shot so you have an ideal area you'll be able to add text without disrupting the subject of the image.
For #2, if you are going to do a pin with multiple images of your project, you are going to need to make sure you take a variety of photos (different angles, backgrounds, etc). Also, take images that are long vertically and horizontally, it's fun to have variety in your pin.
For #3, you should probably be fine as you should be taking step by step images when you make your Instructable anyway ;)
Before you go to make your pin, you should also make sure your photos are edited, if that is something you do. You want them bright, in focus, and all-around appealing.
Jessyratfink has a great Instructable on basic photo editing to get you going.
One last note, when you are making your pin, do not leave the browser! If you do, everything will be lost as you can only save it when you are done.