As I said up post they are good considering they are taken on a phone, but as you asked for it, here is some hopefully constructive feedback. (Please don't be disheartened I'm being 100% honest, and it's just my taste / opinion)
Dog with Cars in background
I like the stance of the dog, and the leading line of the wet path and the colour tones. I don't like the background, and the right hand side of the dogs face is a little black crushed which has lost detail. (not that you could do much about it with a phone, unless you had a reflector or flash). I can also just smell a hint of wet lab!
Dog on Riverbank, head turned
I like the composition, but image looks under exposed, and distractingly not straight.
Dog with stick on the ground, log grass in the background
Generally like the composition, like the stick, but find the dog's position a little odd as it looks like his tail has been docked.
Dog looking to camera, water behind
Probably my favourite, like the composition, the stick and the level horizon. but looks under exposed / crushed, bit soft on the dog's face, and the post with the "5" is distracting.
Once you have your DSLR, the best tip I can give is be brutal on your evaluation and culling, don’t be worried if you shoot all day and have nothing worth keeping.