There are four main ways to stop or slow down a skateboard:
1) The first way is to ride out your speed. This assumes that you have enough pavement ahead of you to slow down. You can further reduce speed by carving and air braking with this technique. This is the slowest way to stop a skateboard and will obviously not save you in an emergency braking situation.
2) The second method is foot braking. The main advantage of foot braking is that it is relatively easy to learn and can be used when riding in “tight quarters” such as sidewalks and other areas where lateral movement is limited. Read this step-by-step on Footbreaking. But, at higher speeds, footbreaking won't work.
3) The third method is running/jumping off your skateboard. This should only be used as a last ditch effort to save yourself. You can only safely run off your skateboard if you are traveling at a speed which is slower than the speed at which you can run. The folks at Timeship racing recommend that you practice rolling onto your protective pads and back while running on grass. Be prepared for injuries when you use this technique.
4) The fourth method is sliding your skateboard. Sliding is the most effective way to slow down or stop quickly while skateboarding. Sliding is not a trick, but rather is a skill which has revolutionized the skating / longboarding world.
The focus of this article is to review and teach the Coleman Slide for the primary purpose of safety. Once you are safely performing this slide, then you can concentrate on your slide style and attempt other types of slides.