Buy a good lens
It’s not always your fault that you can’t take a sharp photo. Sometime its also because you don’t have a good lens. If you don’t take care of your lens it usually gonna reduce the sharpness it can take. Even worse, you can break it.
It also the same with buying a old camera lens. Even though you can attach it to your camera, but usually doesn’t match and it cause an unsharp photo.
For that I recommend for you keep your lens in check. Or buy a brand new lens, not the second hand lens.
Well I didn’t say you have to, but if you can … why not.
Use a Tripod
One of the reason you can’t take a sharp photo is because your camera is shaking, wether because of your hand or thats how it is. That’s when a tripod come in.
Using a tripod can help you have a better shot and control your camera more better and easily. And what best is keep your camera still, prevent it to be shaken.
That’s why for landscape photographer wether you are into nature or city and architecture, a tripod is neccesary to bring. Because sharp and precise photo is important.
Use Deep Aperture
Usually this is what happen. When you want to take a photo all you think about is to have a normal exposure. But in landscape photography that is not the only thing to consider.
I usually prioritize the aperture setting. Because of the depth of field (DoF). Its basicly mean the focus range from your camera that the camera can focus on. So it mean you can create more focus image if you using deep aperture, like f/16 or less (the number more higher). But not so deep as far as f/25. I never use below f/18, because if you use a really deep aperture, the result will be less sharpen.
Find a Sweet Spot
In every camera lens there always a sweet spot. What its mean is aperture setting that make the most sharpen image. For me, my lens sweet spot is around f/9 or f/10.
Its not always the same for every camera lenses. The most accurate way to find it is for you look for yourself. Check out the result with different setting and check out the most setting that work out for you.
Digitally Zoom your Camera
Obviously it wont work for analog camera. But I think this is the best way have a sharper image. I don’t know how every camera do this. But you can do this if you’re using digital camera.
With this you can check if your camera has focus and sharp right. And you check it directly from your live view or your viewfinder (if your viewfinder is electric).
Even though I said before that auto focus not always work, but the fact remain that auto focus is the most easiest way to have a sharp image.