I know you forgot a few things before you launch:
- Make sure you are caching stuff that doesn't need to be retrieved from the persistence layer on each request
- Make sure all your objects in session are Serializable. If the production environment is clustered, you'll need to make sure everything you put in session is Serializable
- Optimize your JVM (http://blogs.sun.com/watt/resource/jvm-options-list.html)
- Optimize your web server configuration (Apache: http://httpd.apache.org/docs/2.2/misc/perf-tuning.html, IIS: http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/71490aae-f444-443c-8b2a-520c2961408e.mspx?mfr=true)
- Optimize your application server configuration (Tomcat: http://search400.techtarget.com/tip/0,289483,sid3_gci1000892,00.html)
- Reduce all Log Levels to ERROR instead of DEBUG
- Make sure you have indices on all the right spots in all your queries
- Create your DNS entries and figure out your cutover strategy (DNS based, VIP in a router, Soft launch of a live URL, etc.)
- 404 and 500 Error Pages. Make sure the content is approved by the Business :) These can be important pages during a site redesign and transition!
- Compress response and request content
- <help me out and think of more things that we always forget to do>
