When you have picked a field you want to freelance in, the next question is: where will you find your first clients?
If you’re in the same field as your current or previous job, don’t try and steal clients from your employers! This is plain bad taste and can even be illegal. So you could get into serious trouble.
One way I have found my first clients is through online networking. Google your industry + forums. Bookmark those sites until you have about 10-15 potential online forums. Sign up for maybe the top five based on relevance to your services and number of forum members. You’ll also want to make sure the forum posts are recent and active.