Answer: No matter whether a geographic move is across the country or to a new city within the same state, firms need to be convinced that an attorney has a personal connection and serious interest in the new geographic location. It is of utmost importance that you convey this connection in your cover letter and again in your interviews. The absolute last thing a firm wants is to bring in a new attorney, train this attorney for a few months, and then have the attorney realize that he/she is not happy in the new locale.
Here are some considerations:
Do you have the California Bar? There are states that make it relatively easy to waive into their Bar membership. California is not one of them. A great way to prove your commitment to your move to the West Coast is by taking the CA Bar. This is not an easy test and it's not cheap, so the fact that you have gone through (or are going through) this process demonstrates your resolve.
Some attorneys say they are amenable to sitting for the Bar if they see interest on the part of the firm. This is the wrong way to view the situation. Some firms will not even consider an application if the person does not presently have the Bar. This is more pressing for litigation positions, but can also be true for transactional openings (depending on the firm). No matter your level, if you are truly serious about a move to California, sign up to take the next possible California Bar Examination.
Are you from California or do you have family there? If you are originally from California and seeking to return "home," this is the absolute best reason to provide a firm. Having lived in California before, you have intimate knowledge of what daily life is like in the state and have made an educated decision to return. If you are coming home, most likely you also have family and friends in the area. This enhances your connections to the locale and makes it less likely for you to leave in the short-term.
If California is not your home, but you do have a familial nexus in the state, this is the next best argument. If your parents, a sibling, or close extended family now live in California, this is also a compelling explanation for re-location. Barring this, look for any close friends that live in the state.
Does your significant other have family in California? This explanation can cut both ways. If you are going to use the argument that you are seeking to move to be closer to your partner's family - there is a slight word of caution. If this person is your wife/husband, this is not a problem and is a viable reason for re-location. Essentially, you (as a couple) made a decision to move closer to immediate family. However, if this person is a girlfriend/boyfriend, firms are concerned that should the relationship split, you will want to leave the city. A job search certainly isn't a reason for engagement, but if you say that you are moving to be closer to your fiancé's immediate family, this holds more weight than "girlfriend or boyfriend." If this individual is not close to being a fiancé, you will want to leave your significant other out of the explanation.
Have you visited California? You have never lived in California and do not have any close friends or family in the state. What now? You should at least be able to represent that you have visited the state and, specifically, the desired city to which you wish to re-locate. Express your enthusiasm about the locale, how much you love the city, and that you absolutely see a future for yourself there. On an interview, your desire to move will certainly be a major topic for conversation. Feel free to be specific about why you love the city (the parks and restaurants you enjoy, art galleries or sporting activities, etc.) and, even in what neighborhood you see yourself residing.
There are, of course, work related reasons why you might want to move to California. Several cities in the Golden State have extremely active markets and you may be confident that having a platform in one of these cities will help you build your practice, originate business, and propel your career as a successful attorney. Please include the work related reasons in your cover and interview. Even so, you will want to find a personal nexus, if possible.