If you have used the archive setup of tomcat then you the file catalina.bat (tomcat\bin\catalina.bat) where you can add your extra configuration: SET JAVA_OPTS="-Dfile.encoding=UTF-8 -server -Xms512m -Xmx1024m -XX:NewSize=256m -XX:MaxNewSize=256m -XX:PermSize=256m -XX:MaxPermSize=256m”
If you have installed tomcat using the installer provided for windows then you will not have this file. In this case you can use the tomcat7w.exe (also from tomcat\bin) where in the Java tab you can set up all that you want (this second option also works for the first case).