I have written out my exact notes that I used when upgrading from 10g to 11g. Although there might be differences and you should most definitely check the documentation, there will be a lot of similarities and this guide will help you upgrade.
[url http://www.ora00600.com/articles/10g-to-11g-database-upgrade.html] Oracle 10g to 11g upgrade
Also, this might not be relevant to you because you are already on 11g but there was a new [url http://www.ora00600.com/scripts/11g/10g-to-11g-upgrade.html]Resource Manager Plan in 11g which was enabled by default and it caught me out after we had rolled the upgrade to PROD so check for that.
Read through all the guides and write down the parts which apply to your environment and do the necessary checks. Once complete, you should have a full list of what needs to be done and in what order. Then double check it. Only then should you start attempting to upgrade your DB, even if it's DEV. An Oracle upgrade is where the saying "If you fail to plan, you plan to fail" comes from...If you don't plan it out properly I can guarantee you that it will not work first time.