Hi, and welcome to the forums.
At a casual glance your scene looks pretty sharp, particularly in the foreground. Examining a scene at 100% on screen is often a recipe for frustration, however, with many images. Unless you have everything under your direct control (eg in a studio), there are too many things that may have a negative impact on what you see in outdoor shots - the light, the air, subject movement etc etc.
Originally posted by sarahswyer Aperture: F20
This kind of aperture might be contributing to the lack of sharpness you describe, due to diffraction. f8 would be fine I suspect for your current scene, delivering you plenty of depth of field without necessarily introducing any softness.
I'd also bump the shutter up a lot to remove any possible camera shake or scene movement. 1/250 would be a good baseline, particularly if the scene is windy, whilst still allowing you to keep the ISO very low in a bright scene.
A good sturdy tripod may also help improve image sharpness in landscape scenes, if you aren't using one already.