I often get emails from people who've seen my train drawings, asking for advice on how to go about sketching strangers in public.
So, although I have probably said a lot of this before, in bits and bobs, I thought I'd put it all together, to maybe help give people the confidence to have a go.
Firstly, I never, ever ask permission: if you do that, you're stuck drawing a 'portrait', which is a totally different thing; people are no longer natural, plus there's suddenly an expectation on you to achieve a likeness (as well as a need to make sure it's flattering!), which makes things quite stressful.
My 'victim' sometimes works it out halfway through, but then they tend to hold the original position and carry on with what they were doing.
There are tricks: firstly, I have found trains are perfect - when people are travelling, they have less objection than when they're 'at leisure'. It's dead time, so somehow up for grabs. I know sketchers who've been challenged for drawing strangers in a pub or restaurant: people can feel you're invading their privacy in these places.
I plucked up courage to try sketching at the hairdressers once:
Another situation I like for sketching is live musicians. They are normally too involved in their performance to worry about me and I've been given quite a few free albums when I've shown them afterwards:
Try not to rub out - it makes a mess and takes up valuable time. If it goes wrong, either draw over the top, or move to a new bit of the page. Also, have 2 or 3 sketches of the same person going at once on the same page: that way you can jump between them as they move about:
Remember: the first sketch is the hardest, so screw up your courage and just make a start. You will get better too, honest! If you still feel too self conscious, why not get together with friends and do a sketchcrawl with friends?
You can view a selection from my various sketchbooks on my website and I have created various short films about how I use my sketchbooks, which might be useful in getting you inspired.