Nah, I don't think "nice tattoo" or "I really like your tattoo" would have so much of an effect. Most of these girls, especially the hotter ones, have already heard these phrases a million times. I think an opinion opener about tattoos would be better. Something like "Do you think tattoos should have a meaning behind them" or "Are tattoos supposed to mean something". In my country, for example, many people have tattoos just because it looks cool, not because their tattoos have some meaning behind them.
Another way to get the conversation going is to simply ask about the meaning. I myself have a tattoo and when someone says "I really like your tattoo" I automatically answer "Thanks", but if someone asks about the meaning I start to show/point the parts of my tattoo and explain what each one means and where is the whole conception coming from.
You can also use the tattoo to neg the target.
P.S. don't take this as an expert opinion, I'm new to pick up, but it's just the way I think in this case. I hope that some of the more experienced guys will post their opinions to help you
or somone else on this forum )