Focus 1/3 of the Way Into the Scene
Learning techniques to focus well is probably a bit more complicated than you might think, however there are a few old chestnuts that will serve you well.
For landscape photographers, focusing roughly a third of the way into the scene will usually give you the best results. This approximates hyperfocal distance which is a more complicated way of finding the perfect place to focus.
Note: Don’t focus to infinity as this can make your shots soft.
Learn Hyperfocal Distance
Now, this is a brief into to calculating hyperfocal distance, but if you want a more comprehensive overview, then have a look at our article on the subject which, coincidentally, applies specifically to landscape photographers.
The short of it is this:
That might be a little complicated, but it is worthwhile for a landscape photographer to learn it and apply it. Approximating it with the 1/3 advice above is great for starters and often enough to get those sharp shots, but hyperfocal distance calculations are for when you want to be absolutely precise. Of course, you can always grab an iPhone app to make it easier.