there are elements to an effective approach and there are common elements to an ineffective approach. I'll type out some of these. Bold things mean this is gonna go somewhere. Italicized means it is probably not.

...

a relatively blank mind before the approach

analyzing the situation, thinking hard, imagining the possible outcomes

...

Approaching in a demeanor that assertively establishes you're here now.

approaching in a timid demeanor

...

What you say is unique to the specific moment

What you say is clearly scripted ...

You're close enough to easily reach out and touch her

you're far enough back that you have to take a couple steps to be in contact with her

...

Your demeanor makes it very clear you're attracted to her

You're just messing around and having fun with a new buddy

...

You assume attraction if she's still there and comfortable after you communicate attraction for her

You wait for her to give super strong IOI's, and validate you explicitly before you assume attraction.

...

She says stuff like "what's your name?", she laughs at things that aren't jokes, she negs you.

she says stuff about you being "sweet", and "nice"

...

You take in how sexy she is, and possibly start to get hard.

You pretend like you don't have a cock and she's not a girl, ignore how sexy she is

(worse than this even is a middle ground between the two extremes, that middle ground is awkward and uncomfortable, leads to creepiness and sleaziness. So you've got to embrace the feelings completely)

...

Direct vs. indirect is a case by case decision based on what feels more socially normal.

you're either always direct or always indirect. Mostly due to which one makes you less nervous