Email your competitor sites owner to exchange link with your site & see what happen. Link exchange always work good for rank well in search engine.
Position No. 4 is not bad. Reoptimize page's title so it looks better on serp than your competition and you will get more traffic
# Use Google Sitemaps to see how Google sees your site, when it was last updated, whether you have any problems on your site, etc. I've written an article on this topic: How to Improve Site's Ranking with Google Sitemaps. You also want to provide a sitemap for your visitors.
Please explain that your Pagerank is 4 or your site rank is 4. It is impossible that you have 4th site rank.
keep posting good quality contents in your site , get good quality backlinks in this way u can improve ur site rankling
1.Use Google Sitemaps to see how Google sees your site. 2.Get involved in communities relevant to the content of your site. 3.The head section of the document should include meta entries for keywords and description. 4.Publish articles on other sites relevant to your expertise. 5.Sometimes your site competes with many other sites for the same keywords. 6.Learn from your competitors. 7.Once your site is established you should try to get other sites to link to other sections of your site as well. 8.Try to include a few outbound links to high quality sites in every document.
I think the best way to improve the ranking is to get the quality backlinks for the website so you can make use of the different seo techniques to get the quality backlinks for the website.
Does your site deserve to be #1? It sounds like 3 other sites are doing just fine. Why should people ego to your site?