Don't talk just pick a card

I was thinking a sponge hare palmed, walk upto someone and say excuse me you have a hair on your shoulder, or you have a hair out of place, then produce the hare.
I produced a ring sized ignighter for one street magician.
He would cough through his hand and a burst of flame would appear, he would look at them an say "nasty heartburn". That always got a reaction.

I have two ways of introducing myself:

1.)Formal-Version (e.g.: if I get booked in restaurants as a walk-around act, but also sometimes used when I'm doing street magic and "disturbing" someone who is just enjoing a cup of coffee ): "Hi, I am a magician, do you want to see something."

2.) Fun-Version: Here I just walk up to a small group of people who obviously are not in a hurry, do a flashproduction of cards/coins etc. and then go in a small routine.

Both versions work fine for me and which one I choose only depends on my own mood. But in my opinion as long as you are nice, your introduction does not offend and always treat them respectfully, it really does not matter what you say as an introduction.
-Alex

Doing flourishes might help to open the conversation.

I know what you're thinking, who is this guy and why is he wearing this shirt. I wear a ****e Shirt from the UK which really stands out.

There are a few rules "Pick up Artists" use to get into the "set" with magic.
Rule number 1: Don't approach saying "Do you want to see a magic trick?" answer will be: "Hell, no...what the hell?"
Rule number 2: Don't feel like a king after gaining all attention and be just a magic nerd (isn't that important for an entertainer - but to have the chance to talk with the girl it is crucial)
Rule number 3 (Thats the rule you're looking for): Approach the group with a simple magic unrelated question like "Do you have a lighter?" and then turn the lighter into a living dove or something ... or ask for some change and switch it to a 100 Euro/Dollar bill...

Loudly sneeze a giant sponge ball into your hand (or a bunch of little ones that fall all over the ground). And, of course, don't forget to use that handkerchief you magically just pulled out of the air

"Do you like to be AMAZED?"

I think confidence and proper outfit (ie. Clothes which are saying you are a magician) would do.

After that just say "Do you believe in magic?"

Perhaps that's one way of getting a girl's number. Kidding.

I do contact juggling with a large acrylic till I get a crowd then start a little pre show to condense the crowd then do a really short like 3 trick "acutal show"

I love the idea and always do the same. Actually people don't love to talk enough before they know a little about you. You can skip this step by doing some charisma.

Your dress (how you dress) will help a LOT. I dressed as Carl from SlingBlade one Halloween and just walked around the streets of Gatlinburg, TN on Halloween night. I started getting stopped by people, so I started patter, lines from the movie, in my pretty good Carl voice. From there it just spiraled.

The term "street magic" is a misnomer. What was once called street magic, is in fact busking. What we now call street magic, is in fact ambush magic.

If what I'm saying is valid? Then when ambushing a prospective spectator the idea would be to immediately grab their interest. Something like "you have nice eyes" "can brighten them even more by showing you something" is appropriate. The same tools work for walk around magic but aren't as important.

Just my 3 cents for what it's worth?

I usually try to adapt to the setting.

At the bar, I will sit next to the victim with a soda can or whatever and do the "a b c d" thing with the tab in a normal voice so that they can hear me. But I don't remove the tab, I pull a spare one that I have hidden in the finger holding the can. Then I casually ask "what's your name?", they tell me and as I probably failed I say oh ok, let me try again (usually I fail again at getting their first letter). But they are so confused thinking "what... I just saw you pull the tab and you left it on the table..." Then I go on with more.

In the street sometimes I disguise as one of those guys performing a poll or whatever. Ask them their name and I perform the One Ahead on them.

Just holding up a sponge ball or sponge bunny is usually enough to get one or two people to stop. And once you get into your routine, others will stop, too. Whenever I go busking, sponges are my big money-maker.

My costume/ clothes imply magic and I make a bee line for families with kids. I ask the parents if the kid could help me out with something, and launch into the tricks from there.

"Could I borrow this ?" produce a silver morgan and start the one coin routine, especially good for terraces, pubs etc...