Ranking drop a lot, how to get it back?

[uoften]

Last year, our website had a fine reputation; but at the end of last year, it droped. No matter how hard we worked, but it seems very hard to get it back right away. Is there any good way to do that?

[mactd]

Check all your backlinks, and make sure they are still on. What are the competition? Maybe it has increased now.