By default Tomcat distribution comes with a very naive configuration settings, because everything is set to default. The first thing that should be modified are the JVM memory configuration settings. JVM is an environment in which all Java based applications are executed. JVM often could be located by analyzing the JAVA_HOME environment variable.
In order to increase the performance of Tomcat you should modify JVM memory configuration settings. By default some predefined size of memory is allocated to JVM, and if you need more then this amount of memory you will not get it. Often the default memory size is 64MB.
By giving more memory to JVM you can increase the performance of your Tomcat. You should use the following command line parameters -Xms and -Xmx to set the minimum and maximum size of memory allocated to JVM. You can check to see if the performance of your Tomcat was improved after those changes.