You don't need any skills to do this job, it is just a case of walking around for hours on end with some advertising windshield equipment hung you. The pay isn't that good, but then what do you expect from this kind of job. This is the picture most people get of sandwich board advertising work. The classic portrayal of a sandwich board advertising to me was the advertisements that preached 'The World is Doomed', this of course religious extroverts on a mission but it still rings bells in my head.
For a more definitive description, the job could entail, wearing signboards and walking amongst the public to advertise merchandise, services, or belief. The job might include distributing handbills to passers-by or/and wear costume to attract attention. There is also work that is contracted through labour organizations as a designated Picket for certain Labour Unions or Religious movements.
Many people actually do this job not for the love of the job but solely for the money. In London you can get up to £5 an hour for this. Minimum wage stuff really, but it is money all the same. Many unskilled expatriates who flood into town and cities take up this job as they can't speak English and can put up with the boredom it brings. This pays for their food and rent, but not much else; they seem quite content with this work.
If you are desperate for extra dosh then this may well be a card up your sleeve that you can use. As for a full time profession, you won't get any stimulation from the work so you might want to do it for a short term.
Some have described this job at the worse they have ever done, but I feel that is an over-statement and made from those who just did the job to give them something to write about. There are far worse jobs than this and for poorer pay. After all you are actually getting paid for walking around doing nothing so it can't be that bad.
Much of the work advertising through the sandwich board medium is now geared towards bigger billboards, not just sandwich boards. These can be as tall as three metres as more people in crowded streets will see the ad. This of course means that there is more effort needed in carrying it around and indeed can be quite hazardous if dropped or taken away with a strong wind.
It may be that this kind of work is now going to become extinct in some cities. London has already taken steps to ban sandwich board advertising in Westminster and this may well spread to other areas of London, then springboard into other cities.
If you have time on your hands, live in a big city and don't mind walking the streets as the meat in the sandwich, you may want to try this work. The best method to find this kind of work is to look in the local shop windows for ads, check out your local job centre, or the most effective way is to look for other sandwich board workers and go to their sponsors' workplace and ask for work there.