You know if your website is very well built with a huge amount of info I really think writing a few press releases may be useful. Directory is good though not for relevant backlinks, stick with everything you know about blog promotion and then build a link directory and begin swaping links with relevant sites. Social bookmarking may also be helpful in your campaign.
do you guys have any creative ideas specific to financial websites? especially stock trading? i've heard most of the advice given so far. i'm wondering if anyone has any ideas around financial websites specifically.
@MysteryLeo - You have a nice site there. Maybe you can identify forums & blogs in the same niche and start to be a frequent visitor who leave comments there so that people will visit your website and use the features that your website provide. Maybe you can even do a case study in a stock market forum and say how the tools in your website help you to get better return on your investment.