I'm no pro either so I am going to just make observations not suggestions.
I have found that when I am shooting in P mode (about 90% of the time) That I can get tremendous variation in the exposure depending on where the spot meter is. In your first picture (which by the way looks pretty well exposed except for the center white flower) you have alot of range of color. From very light to fairly dark . I think that you'd find that your exposure through the view finder would jump all over the place depending on where the camera was metering the light. If you do have spot metering on then maybe try the multiple mode to spread the exposure metering over the whole scene.
The second picture does look a little washed out but there seems to be quiet a bit of haze in the picture. So, that is going to make a perfect exposure very difficult. The light tends to get scattered quiet a bit from the haze and the atomosphere is much opaque. Probably filtering the light either on the camera or in Photoshop would make the exposure look more natural.
As I said I'm not an expert either. Those are just some observations I have made over time.
The more you shoot the better you get.