your subjects and poses are good as is your framing (though 3 feels a little tight on the lefthand side) - and really like the silky look to the dogs fur.
However what is really distracting is the sky - in the first 3 shots you have done well to expose for the dog and not blow its whites - but the sky in each case is dull and sucking the life out of the shot -- I think this is partly as you shot in a cloudy day for the softer light (good thing).
I would recomend shifting so that you have a background like in the last - ie where the grey sky does not show and you can expose for subject and keep an interesting background.
Its a shame that in the last you overexposed the dog.
I think these shots show a lot of good methods and I would simply try moving to a position where you have a better background = or you could try shooting during a clear day with a polarizer on the lens to keep the sky blue
Nice model, beautiful dog. Like the composition in these. Your profile says photos are ok to edit so hope you don't mind. Cropped a little closer to get rid of the sky and applied s-curve in #1 and adjusted highlights and shadows and dodged the midtones in the face a little in #4. Just my take on your pics.
I agree, the second one is very good. They both seem happy in it. Same with the last one, but I like tran.crisses edit to help smooth the dark and light areas.
And the dog is absolutely gorgeous (girl ain't bad either)!