Find the middle ground between approaching an angry looking woman wearing headphones and typing on a laptop versus waiting for a declaration of love to approach
Both of those extremes will get you nowhere
The only IOIs you need to watch out for are ones that generally lack ambiguity. Stuff like compliance or letting you escalate or if she's willing to be 5 minutes late to whatever shes doing to talk to you, or something.
Likewise don't get yourself rejected needlessly, it'll only crush your spirits. Only do approaches where you think you at least have a chance (learn to spot wastes of time) and use failures to calibrate appropriately (for example, i have a bad track record for girls with laptops) and learn from mistakes (bad openers, bad closing, bad jokes, bad reading of signals/signs/hints, etc.)