How to make a long shadow effect
Make a long shadow in Vectornation by Zaweba with Effect > Stylise > Long shadow, a live effect for flat icons, lettering and badge designs.

Long shadows live under Effect > Stylise > Long shadow in Vectornation by Zaweba. Select an icon, a word or a shape, apply the effect, and a shadow stretches out from it at an angle, the look made popular by flat design. It's a live effect, so it follows the artwork if you change it and can be adjusted any time.
A long shadow is a solid, usually slightly darker band running from the edges of an object to a far edge or off the page, as if lit by a low sun. Drawn by hand, it takes careful work with copies, blends and the Pathfinder. As an effect it takes a second.
Applying the effect
Select the artwork. A long shadow works best on a simple, bold shape, such as an icon, a letter or a short word in a heavy typeface. Choose Effect > Stylise > Long shadow and set it up. The classic look runs the shadow down and to the right at 45 degrees, long enough to reach the edge of the background shape if you are working inside a circle or square badge.
Choose a shadow colour. Rather than black, use a darker shade of the background. Long shadows look best when they read as a deeper version of what they fall on.
Keeping it editable
Because it is a live effect, it appears in the Effects and Appearance panels. Click it there to change its settings. If you edit the word or swap the icon, the shadow redraws itself. That makes it easy to try a few angles and lengths before settling.
Shadows and glows in Vectornation are also easy to click past. Clicking only on a shadow selects what is underneath it, so a long shadow that crosses half your design won't keep getting in the way when you want to select the background.
Making it look good
Clip the shadow to a badge. Long shadows are usually seen inside a circle, rounded square or other container, with the shadow cut off at its edge. Put the icon and its shadow inside a clipping shape the same as the badge.
Fade it out if you like. A shadow that becomes transparent towards its end looks softer. Use an opacity mask or a gradient for this, depending on the look you want.
Keep the shape simple. Fine detail produces a messy shadow full of thin slivers. If you are using text, a bold font with few thin strokes works best.
Related effects
Long shadow sits under Stylise with Stipple, which turns artwork into dots. The live effects in Vectornation also include a regular drop shadow, feather, inner and outer glows and Gaussian blur. A drop shadow is soft and short, for lifting an object off the page; a long shadow is hard edged and graphic.
The two can be combined. A long shadow for style and a small, soft drop shadow under the icon for depth is a common pairing.
Sending it out
For the web, export SVG or PNG. For print, export a PDF. If the file is going to someone who might open it in a program that doesn't understand Vectornation's live effects, send a PDF or a picture as well, so they see it exactly as you designed it.
Long shadows are quick to overuse. One on a set of icons gives a family look; one on every element of a page gets tiring. Used with restraint, it's an easy way to give flat artwork some depth, and Vectornation by Zaweba keeps it editable while you decide.