Hi Chris,
Some nice images (I like your automotive work best). From your 'sort of business' comment I imagine you are in the transition phase between amateur and starting to look for photo markets, This is a route many, many people go after they get a few hundred images under their belt and acquire some tasty equipment. I spent about 5 years as a keen amateur in my late twenties and then spent the next 30 years in the 'pro' arena - high street studio, weddings portraits, model portfolios,CD covers, magazine commisions etc. My early years were with film and the last 10' digital, including many many hours air brushing ladies' faces! I am now retired. The competition out there is fierce and the standard of photography, even from many amateurs is often fantastic. The old advice of going to work for a top London studio/agency as a junior and then after learning the trade, branch out on your own is still partly true. However an intelligent web presence is now almost as valuable. One thing I will point out is that my most enjoyable images were probably made before I turned pro. The competitive world will hit hard - make sure you want dog eat dog and if you are OK with that then.....go for it. Too many amateurs give up their day job and think going pro is all they need to do. Very few make it because photography is such a pleasant activity and so many want to be 'photographers' rather than do 'ordinary' jobs. My best advice is to 'study' with a specialist (wedding, advertising, medical.... whatever) - you will learn so much so quickly. Study the best online images and find out how they did them and aspire to these standards. Study with those who 'know how to make cash from their camera' - there are many who give advice but earn very little. Having said this many amateurs never seek to sell their photographs and yet produce work of staggereing quality. Commercial photography is not always the best but it connects with a market and that is the crux of professionalism. I wish you all the best and even if you do not decide to go down the business route....enjoy.