My advice is to not do an in-place upgrade. The benefits of an in-place upgrade are that you don't need to change any connection strings in your applications and it uses less disk space. The downside is a rollback involves a lot more steps if something goes wrong and it is a lot harder to do a side-by-side comparison for performance.
My preference, where possible, is to do a migration upgrade. Involves more disk and application level changes, but makes rollback if something goes wrong very trivial.
Either way, the upgrade should go fairly smoothly. Might not hurt to do some analysis on the databases prior to upgrading to ensure you have no deprecated features in play or unexpected behavior changes (database migration assistant can do it for you but is a bit of a resource hog and can crash randomly).
My biggest tips are ones you probably already know. Once you are done the upgrade, don't forget to change the compatibility levels and update statistics and take a backup. Upgrading SSIS, SSAS and SSRS should be mostly painless, but with SSRS I'd make sure your encryption key backups are up to date just to be on the safe side. Don't want to upgrade and find out all of your reports are busted.