Using your technique, you could use a transition between asking advise about the vase for your mom and then notice something about her. Like a neckless or bracelet and be like "omg thats the nicest neckless ever, my aunt used to have the same one" and continue telling a bullshit story about your aunt and transistion into nephew or niece and how they mean the world to you.

Also if you are handsome it doesnt matter what u say, you will get away with anything, like telling her you have a giant boner right now for her, she will love it

If you are ugly it doesnt matter what u say, you will get away with nothing. She could call the police just because you said "hi" and how dare you thinking you had a shot with me