your best bet is to get a few cars done that go to shows, get some stickers in them advertising your company and if people are happy with your work they'll come to you. word will spread quickly if your sprayings good and you offer good customer service.
I agree, the only thing with this line of work is that its a lot more expensive than people think, from the start on a full exterior re-paint. At least half a day to strip the car bumpers off ,mirrors,door handles, mouldings etc. Go round and and tap out dents and do repairs, most cases at least a day. Then mask up whole car and prime repaired areas. At this point alone your up to around £400 pounds in materials and labour. Then comes half a day prepping the rest of the car and what you have primed with another half day cleaning and masking up. Then the expensive part starts. For you clio sized car you are going to be using around 3 litres of colour at the cost of £50 per litre plus the cost of thinners which is going to be 1.5 litres at a 2-1 ratio mix meaning another £25. Then there is clear, depending what sort of finish you want this can cost anywhere from a £140 upwards without hardener, then the cost of tac rags,paint filters and all the other little bits and pieces. When finished painting and baked off comes another half day de nibbing and polishing. As you can see there is a lot of time and money involved, i will probabley get loads of abuse now saying why would it take that long bla bla only to be told I do things properly and I dont use s**t materials. Hope that helps.