Some window cleaners look like scare crows, and to be honest, I've probably been one of them; now and again.
But we've smartened up and wear the same polo shirts, fleeces and shower proof jackets. It doesn't take much to cobble up some sort of 'uniform'.
Recently we had to quote for a large posh hotel, and we both turned up in polo shirts, jeans and polished boots. Shaven and clean. We got the job (after we jumped through hoops, ate fire and juggled) - but I'm sure our image helped some.
Other (local) window cleaners have made friendly fun of us though!
I think as long as you look clean, shaven and non-threatening, you're half-way there. Would pensioners ask you to clean their windows if you have facial peircings and tatoos and owning the 'heroin chic' look? Some would, but plenty wouldn't.
As for keeping warm - you need to do the 'layering effect'. Lots of thin layers - that you can remove - one by one - if you get too hot. Keep the layers hidden under an outer shell - like a fleece. One thick and heavy item of clothing might be 'too warm' and if you remove it, you'll be too cold.
Wear a wooley hat too (although I haven't had to so far this Winter) - preferably without a bobble. They say you lose 70% of your body heat through your head!
For gloves, see the gloves thread.
Thermals are good too.
Oh, for holding money, phone, pen, invoices, nicotine chewing gum, head phones etc - I use a bum bag. Jeans pockets are a pain to get stuff out of - especially while wearing gloves.
As for scrim, I use an unger belt with two pouches. One on the side, and one on my back. Just load them with scrim and off you go. Some of the guys on here will only use one or two scrims a day, but I'm not that good yet. Give me a few more years. Me and the missis can still get through a bag full a day and we've been at it for a couple of years.
For my sill cloth, I cut a towel into smallish squares and tuck one into the loop on the side of my pouch - it stops it from making my scrims wet. I tend not to use it too much these days as I squeegie the sills!
In Summer we wear shorts and polo shirts and I can't wait to get in them again!