Using Meta tags
Always use meta tags title , description , keywords on every page of your site.
It should contain keywords and phrases with keywords.
Using tags <h1>…, <strong> ,<b>
Titles with keywords (credit cards' names, banks' names) always put in tags <h1>, <h2> or <h3> its size and color you may change in css - files.
Use <b> and <strong> to highlight keywords in text.
Content of your site
You better have a lot of keywords on your site. It may be articles or something else that mention credit card , bank , personal finance, etc.
The more keywords you have - the higher is the opportunity to be in search results. And at the other hand, a great number of keywords will increase its weight for a search engine. Actually these articles are not for reading - they are just for having keywords - so don't take it too much serious.
Using Keywords in Domain Name and Pages' Names
It's good if you have 'credit cards' in your domain name. Also try to use it in the names of the pages: low_apr_credit_cards.php best_credit_cards.htm rewards-credit-cards.php…
Get Rid of Links from Your Site to Other Sites
Try not to put links to the other sites unless it is necessary, especially to the sites that are not about credit cards and personal finance. If you put a link then do it with parameter rel =”nofollow”.
Refreshing Site
Search Engines like when your site is not too much static. So, add pages and renew the content. Bots will visit your site more often.
There is always you can optimize at your site.
Links from Other Sites
Try to get as much links as possible (better is it will be with your keywords). Links form 'Credit Card Sites' will be the best.
PR
It's a Google's estimation of your site. The higher is pagerank - the upper is your site in the search results. Try to get links to your site from pages with high PR.
Google Sitemaps
Do your site's Sitemap and register it in Google Sitemaps (http://google.com/webmasters/sitemaps/). It will not increase PR or affect your position in search results and etc. It will only give you a quick indexing in Google's database. It is also good if you have dynamic pages: credit_cards.php?bank=chase&card=visa_gold&page=13.
All you have to do is write a file in XML and register it in Google. You can take our site's sitemap as an example http://express-credit-cards.com/affiliate/sitemap.xml.