How can I be more proactive with women??

Ever heard of the 3 second rule?? I.E you should approach a woman within 3 secs of seeing her

Street approaches are quick,thats okay,cafe approaches tho

It takes me 10-15mins lmao,i still get it done,but I think I can be faster,I just sit there,all anxious,so it takes some time to reframe my anxious thoughts,then I approach

At supermarkets,i often have to linger there,gather the courage,sometimes,I have to make 3 trips around the aisles just to approach her,I dont like it,so any advice