Cathy, there's lots of advice in the thread, some conflicting, some good some not so good.
As an experienced landscape photographer, here are my bits of advice.
Get to know your camera inside out, know it's strengths & limitations, same goes for your lenses, so when you come to take your shots, you are not spending your time having to think too much about the camera's controls, shutter speed, aperture etc, they will come naturally, leaving you to concentrate on whats important-composition & light.
I use aperture priority (a/v) for 95% of my landscape photography, rarely use manual exposure (find no need of it), for me aperture is the most important variable, as I generally use a tripod, shutter speed can take care of itself.
Similarly with manual focus, again find no need for it, modern DSLR have such good autofocus systems that you can rely on them 99% of the time, the only exception is in very poor light when the lens may 'hunt' for focus lock.
If you are serious about landscapes, you
need to invest in a set of ND grads. Cokin, Lee & Hitech or all recognized manufacturers. Yes, you can stack your images, taking different light readings, but generally the results I've seen are less than satisfactory. Plus it takes too much time, while slipping a grad in the lens holder takes seconds. Most serious landscape photographers use grads.
From the two images you posted, it looks as though you have a decent eye for composition, particularly the first. Looking at it on flickr, it looks a little soft, possibly due to shooting at f25. While most of my landscapes are shot at F16 -f22, I use good glass, therefore the lens manages any fall off in quality at small apertures (diffraction), unless you are using a good lens, f25 is really pushing it. To get the longer shutter speeds, I'd go when the light is lower and shoot around f11, alternatively an ordinary ND filter.
Lastly, keep an eye on your horizons, both look as though they are on ski slopes
, easily put right in LR or PS