A note about Defensive Stance - if you’re going to be using it, the Protection skills go with it, invest in a good shield and use it. There are several very good skills, such as Shield Bash, which require a shield Tibia money to even work.
Shield Bash at 64 gives you an attack that does 63 damage, interrupts spell casting, prevents any spell of that school being cast for 6 seconds and dazes the target, reducing their speed by 50%.
If you use talent points here you can also silence your target for 3 seconds, which will prevent all casting of all schools. This is probably your best defense against spell casters, and I recommend using it primarily to stop healing.
When fighting a caster, it’s always a good idea to keep 10 rage ready just for a healing cast. Managing your rage wisely here can keep you from having to start over on a healer.
Or, if you have enough time and quick reflexes, you can sometimes hit Blood-rage to grab 10 rage and then get Shield Bash off.
Some people make a macro for this to help for those times when you just have to do a Shield Bash and you don’t have the rage.