You know, we all have friends in our lives. Some are more closer to us then others. There are friends and there are "best friends". As photographers we own many accessories. Lens cloths, hoods and filters are friends. So are camera bags. But our "best friends" should be two pieces of vital equipment -- the tripod and the remote shutter release.
The tripod provides stability and a better way to accurately compose your subject. Use of a tripod (even a cheap one - any tripod may be better then none) prevents you from having to hand-hold your camera especially problematic if you have a long lens attached to it. Other accessories such as a battery grip can also add weight which only makes it more difficult to hand-hold your camera. Instability leads to camera shake which leads to blurry images.
Another great advantage in use of a tripod is that with the camera stablized, you can now select aperture priority mode (Av) or (A) and concentrate on depth of field (DOF) when capturing landscapes. With landscape subjects, the subject doesn't move and so the only movement you need to prevent is from hand-holding your camera. Landscape subjects require closing down the aperture and the sweet spot is usually around f8 to f11. Ok, no problem. Just be sure to capture a proper exposure!
When you try to capture a landscape scene hand-holding the camera, you need to prevent camera shake and blurry images by turning your len's stablizer (if you have this) to ON and then set a high enough shutter speed using the (hand-holding / shutter speed) technique to stop any camera shake for a clear image. Now, imagine, based on the light in the scene, that you needed, say, to set a shutter speed of 1/250sec based on your focal length set to 250mm. Your camera's software will automatically set an aperture that is wider open say around f4 for this example. At f4, you may not have enough depth of field to give your scenic foreground to background sharpness. By hand-holding your camera on non-moving subjects such as landscapes, you are forcing yourself to use shutter priority mode (Tv) or (S) and now your at the mercy of the camera's software to set the aperture. What to do? Use a tripod!
Your second "best friend" should be a remote shutter release. I like the ones with the cable. Why would you set your camera up on a tripod for maximum stability then decide that you are going to push the shutter button on the top of the camera. When you push that shutter button, you are touching the camera and possibly inducing vibration which can lead to blurry images.
These are the two main ways to prevent camera vibration and blurry images!