Started off in California as an amateur photographer in 1992; by 1994 I was discovering quite the aspiring talent -- just had the right eye for it!
Ended up partnering with a colleague who represented runway models. Zoom to 2012, I am now in UK and Ireland, scouting models.
If you are a model, which you probably are if you are reading this, here are some tips from a middle aged guy who has seen it all:
1. Don't pay money to any model agent/scout! Fees are paid as part of commission, they are never up front!
2. If someone tells you that you have the right look (which can very well be true!), and they tell you to go pay so much for a portfolio, that's probably as far as you will get -- paying money for a port!! Generally, not a good idea.
The best pics for being found are digital pics by a friend. Try out different outfits, and have a friend take some good shots. Also, one photo should show the body well, I recommend briefs/shorts for a guy, and panties/bra or a bikini for the ladies. Your body is your most important asset, so make sure people can see you, not baggy clothes!
Also, make sure one of the photos is a portrait - head to shoulders.
Best of luck!