Exchanging links (reciprocal linking) doesn't work as well as it once used to.
What you need to do now is generate relevant one-way links back to your website.
If you only have a landing page with an optin form, I would suggest setting up a blog on that site and adding content to it.
Your goal would be to get backlinks to the content pieces and then funnel that to your optin page.
You can get links by...
- Submitting articles to article directories
- Creating pages on Squidoo.com and HubPages.com and linking to your site
- Creating videos, uploading them to multiple directories with TubeMogul.com and linking back
- Submitting your blog RSS feeds to RSS aggregators
In reality there are hundreds of ways of generating backlinks.
The one mistake that I see a lot of beginners making though is that their site is not optimized in the first place.
If you want to rank well, your site needs to be optimized around the correct keywords.
Hope this helps,
Richard