To ensure your photographs are sharp, there are a lot of considerations. As a beginner, that can be daunting. In this video, however, you will find some advice on making sure your image doesn't lose any precious sharpness.
James Popsys advice in this video is a trick that can't necessarily be replicated in all cameras, but the philosophy behind it can be.
A loss of sharpness can happen for many reasons, which is why it's prevalent in newer photographers' work. A loss of sharpness can come from too high ISO, motion blur from too slow a shutter speed, barrel distortion, and so on; it can be a minefield. That said, there are key settings that can have parameters enforced to limit these issues.
What the limit of these settings is before you experience a loss of sharpness can and will vary based on sensor size, presence of IBIS, and lens, etc. I would recommend experimenting with your preferred camera and lens and finding where you start to notice an impact on your image. For example, I wouldn't go above 3,200 ISO, below 1/30th shutter speed, or above around f/16. While these settings are a little safe (there are instances where I could shoot the wrong side of those limits without ill effect) they ensure I always come away with a sharp image.
In this video, Popsys shows you how he sets up limiters for each setting so that he can use many settings on auto, and just concentrate on shooting the beautiful vista.
I think there is a problem with compartmentalising "Landscape photography" when it comes to sharpening and iso. Matt Kloskowski posted a recent video on what he has learned and how his approach has changed as he has started to take more wildlife images. I certainly find the constraints on iso, shutter speed and aperture more challenging for my wildlife images than for landscapes and have learned a great deal from taking both.