In order of importance.
- Persistence – this
- On-page optimization – if this is wrong you fail
- On-site optimization – if this is wrong your job is a lot harder
- Off-Site Optimization – if you promote it they will come, probably
- Social Signals – because Google has had it with abused backlinks
What keyword are you trying to rank for? Why?
Who is ranking for it?
Do what they are doing better.