Ok, I will list a few very common situations, these are very newbie questions, and it would be good if someone can give me some suggestion of good ways to open in those situations, and then how to best transition from it...
1) Let's say I walk in the street and see cute girl walking with a dog. It's very common situation... I can go with something like "Hey will he bite?

" .. Is this good (I guess it is, it's opener so..

or can I open with something better, and how do I transition from this kind of opener... Any ideas?
2) I am at the concerts/festivals all the time... So in a few days there is a U2 concert... let's say I spot cool looking girl, with or without some friends... How do you start talking with a girl on festival, and especially important how do you transition, and continue talking. I guess I can open with anything regarding concert, it's not that hard ("Hey, when does the concert start" of "Which are supporting bands") but not sure how to transition, and what more to talk about next.. ?? Or again, is there a better opener, way to start this conversation?
These are two situations I would need help now, cause they are so common for me, I go to concerts all the time, and also there is this one cute girl I already spotted few times near my street walking with a dog, so want to try do something with it..
Any further ideas for this situations (some field reports for similar situations if existing would be great) welcome
Thanks,
Nik