Hi Dimitrz,
All of your pictures were taken "against the light",, resulting in a very high subject brightness range.
You can handle this in a variety of ways:
By using an HDR (High Dynamic Range) technique (don't ask me about this, but you can google for it, its the flavour of the month!
)
By deciding which part of the scene (the main subject) is important and exposing for that: this results in either blowing out highlights (e.g. skies) or losing shadows (e.g. persons silhouetted against bright backgrounds, like your friend in the picture in the mountains). In the picture of the beach, at any time, but especially if taken against the light, you should increase the exposure by +1 to +2ev, using your "exposure compensation" setting.
By reducing the overall SBR through using graduated neutral density filters (messy in the pics provided).
By using fill flash. The simplest to apply in pics 3 & 4. (You should check out your camera manual for how to engage "fill flash" or "slow sychro" flash, and use it in such cases).
Unfortunately, no matter how "automated" the camera, it can't deal with every contingency: you have to help it, you have to learn to "think" like your camera and assist it over the hard spots. Sometimes this means avoiding some situations it can't deal with, or accepting compromises.
