Optimization of the site

Hello.

Do you know some ways to optimize site? I have now memory usage in front site about 10MB. What can I do to make my site more optimal?

Hi, there is few tips which you can find in those O'Reilly Media books:
1) "Web Performance Daybook Volume 2"
2) "Website Optimization: Speed, Search Engine & Conversion Rate Secrets"
3) "High Performance Web Sites: Essential Knowledge for Front-End Engineers"
4) "Even Faster Web Sites: Performance Best Practices for Web Developers"

p.s.
First, you should optimize the site to reduce the memory usage with caching.
Second, uninstall unnecessary modules.
Third, enable gzip.
Fourth, upgrade to PHP 5.3 if not done so yet