A few more specifics would help you determine what the best plan of action is. Keep in mind that it's a very, very subjective process so your credentials might be stellar and for whatever reason (perhaps the fit with the department isn't great, or it just can't accept that many students) you can be rejected.
What'd you get on the GRE? Verbal and AW are wayyyy more important than quant, and perhaps verbal is most important of all (the adcomms will have at least one piece of your writing sitting in front of them, and won't need the GRE to tell them if you are good or not). If you need funding, above 85th percentile is the cut-off for most of the UCs. And another question would be, where are you applying? Different schools have different expectations. GRE scores won't get you into a school on their own, so keep that in mind--if you have a stellar writing sample, SOP and strong LORs, that matters more than GRE scores by far.
Something to consider, however, IS how the rest of your record looks. I knew I wanted to break 90th percentile on verbal because my undergraduate record is good (I got like a 3.77 in history coursework) but not great (3.44 overall), and I'm in an MA program, but I don't have a 4.0 (3.85). So I figured I NEEDED to not give them another reason to second guess my record, as I'm not an impeccable candidate. If you have some minor peccadilloes on your record, a strong GRE score has the potential to smooth those over (a chance, not a certainty...basically, don't give them another reason to toss your application).
Make sure and spend a good deal of time on your SOP and writing sample. These should represent your best and most thoughtful work. If the adcomms see something special in these, something that intrigues them, you're likely to get in regardless of what the rest of your app looks like (let me qualify that with, as long as the rest of your app meets the minimum criteria for admission--and even then, some people with below minimum GPAs have gotten into doctoral programs). There is no set formula, just make your application the best you can. Consider the package as a whole, note your weaknesses and try to strengthen them, and if you can't then augment them elsewhere.
Best of luck!