Depends. Are you sure it's been the Penguin and not a manual penalty? That's a tough one, especially because Google almost rolled out few of these at the same time.
A manual penalty can only be revoked by removing "bad links" and requesting reconsideration through Google's WMT. You may use the disavow option to make sure all the bad links are excluded.
If it's only Penguin, you need better links with natural anchor texts, and remove low-quality (anchor text over optimized) links to balance out the link profile. Then wait for Penguin to recalculate your status (Happened every 6 months so far). But don't expect wonders if you still rely on low-quality links. Even with good links. Nowadays you need the right user behavioral metrics in the eye of Google (CTR, high time-on-site, low bounce rate) to qualify your site for higher rankings, which ultimately breaks down to the quality of your site itself (Do people stay on your site, read resp. spend time on it? Is it attractive/interesting enough?)
You may have great links, but with super low Google user metrics and without natural links that keep flowing in (forget about article and low-end bookmarking sites), you won't move up much, except you own an old site that's built up authority over time, which however got much more vulnerable nowadays if they lack the metrics.
