You can ask other sims in your social interactions with them. On the pie menu, in the "Friendly" interactions! You can choose a few selections, such as, "Meet Prospective Client", "Offer Legal Representation", "Chat about Scandalous Lawsuit", and "Discuss Complex Case Law". I'm not sure about how to successfully obtain a client though. There have been times that I have been successful at choosing "Offer Legal Representation" the first time , and other times were it has taken me several attempts, no matter my relationship level. So, if anyone has advice on that part, that would be excellent!