1. Download the EAP version of JBoss (from Jboss.com not org) and start using that instead of the GA version as you should be using the EAP version for support reasons.
2. Precompile JSPs and ensure that your web.xml does not run them in 'development' mode.
3. Be careful with logging including console logging. Do not have System.out anywhere and tune your log4j configuration so you only receive what you need.
4. Remove JBoss AS components that you are not using. Some examples are EJB, web-console, jmx-console, JMS, HAR deployer, CORBA, etc. There is documentation to help with this ... just search for it.
5. Add the following java option to your run.conf file: -XX:+DisableExplicitGC
These are just my suggestions off the top of my head. I would never take a JEE container to production without serious research on performance and tuning. You may want to even talk to Redhat about either Admin training or having a consultant assist in tuning.
Thanks a lot, it is very helpful.