Well, unless you are really good and well known, clients dont just come by. Networking is perhaps even more important that photography skills at the lower end of this business. If you have little to no contacts, a good way to start off is to build yourself a decent portfolio, and then emailing companies to advertise your services. Out of a 100 emails sent, you can expect to receive 5 meetings with the clients... securing a job is another matter which is up to your interpersonal skills. I'm lucky to know some photographers/art directors who outsource jobs to me whenever they need a corporate or event photographer. In photography, I cannot stress the importance of networking, networking and more networking. You need to present yourself as confident and professional. Start off small first, I would say. My first jobs were through emails.... for example Zoukclub. All the best.