Honestly, wearing my dirty work shirt going to give an estimate has helped me.
New customers have said, "Looks like you've been working hard"
I can then say, "I don't stop!"
They are hiring you to cut grass, look like you cut grass!
Sometimes a little grass on your face can help
I suppose what you wear can have different effects on people. One thing is for sure, having your gear with you looks great - especially if your vehicle has magnets.
If you show up without gear, or magnets... while dressing spiffy... You just look phony.